Research Progress of Pd-Based Heterogeneous Catalysts in CO₂ Hydrogenation for Methanol Synthesis AITranslate

［1］Olah G A. Beyond oil and gas：the methanol economy［J］.Angewandte Chemie，International Edition in English，2005，44（18）：2636.

［2］Shih C F，Zhang T，Li J H，Bai C L. Powering the future with liquid sunshine［J］.Joule，2018，2（10）：1925.

［3］Kohse-Höinghaus K. Clean combustion：chemistry and diagnostics for a systems approach in transportation and energy conversion［J］.Progress in Energy and Combustion Science，2018，65：1.

［4］Zhong J W，Yang X F，Wu Z L，Liang B L，Huang Y Q，Zhang T. State of the art and perspectives in heterogeneous catalysis of CO2 hydrogenation to methanol［J］.Chemical Society Reviews，2020，49（5）：1385.

［5］Studt F，Behrens M，Kunkes E L，Thomas N，Zander S，Tarasov A，Schumann J，Frei E，Varley J B，Abild-Pedersen F，Nørskov J K，Schlögl R. The mechanism of CO and CO2 hydrogenation to methanol over Cu‐based catalysts［J］.ChemCatChem，2015，7（7）：1105.

［6］Monk J M，Koza A，Campodonico M A，Machado D，Seoane J M，Palsson B O，Herrgard M J，Feist A M. Multi-omics Quantification of species variation of escherichia coli links molecular features with strain phenotypes［J］.Cell Systems，2016，3（3）：238.

［7］Kowalec I，Kabalan L，Catlow C R A，Logsdail A J. A computational study of direct CO2 hydrogenation to methanol on Pd surfaces［J］.Physical Chemistry Chemical Physics，2022，24（16）：9360.

［8］Grabow L C，Mavrikakis M. Mechanism of methanol synthesis on Cu through CO2 and CO hydrogenation［J］.  ACS Catalysis，2011，1（4）：365.

［9］Zhang M H，Yin S，Chen Y F. A DFT study for CO2 hydrogenation on W（111） and Ni-doped W（111） surfaces［J］.Phys. Chem. Chem. Phys.，2020，22（30）：17106.

［10］Gaikwad R，Bansode A，Urakawa A. High-pressure advantages in stoichiometric hydrogenation of carbon dioxide to methanol［J］.Journal of Catalysis，2016，343：127.

［11］Zhao Y F，Yang Y，Mims C，Peden C H F，Li J，Mei D H. Insight into methanol synthesis from CO2 hydrogenation on Cu（111）：complex reaction network and the effects of H2O［J］.Journal of Catalysis，2011，281（2）：199.

［12］Han X Y，Li M S，Chang X，Hao Z W，Chen J Y，Pan Y T，Kawi S，Ma X B. Hollow structured Cu@ZrO2 derived from Zr-MOF for selective hydrogenation of CO2 to methanol［J］.Journal of Energy Chemistry，2022，71：277.

［13］Li H J，Wang L，Gao X H，Xiao F S. Cu/ZnO/Al2O3 catalyst modulated by zirconia with enhanced performance in CO2 hydrogenation to methanol［J］.Industrial & Engineering Chemistry Research，2022，61（29）：10446.

［14］Singh R，Tripathi K，Pant K K，Parikh J K. Unravelling synergetic interaction over tandem Cu-ZnO-ZrO2/hierarchical ZSM5 catalyst for CO2 hydrogenation to methanol and DME［J］.Fuel，2022，318：123641.

［15］Song X W，Yang C S，Li X H，Wang Z Y，Pei C L，Zhao Z J，Gong J L. On the role of hydroxyl groups on Cu/Al2O3 in CO2 hydrogenation［J］.ACS Catalysis，2022，12（22）：14162.

［16］Xu Y N，Gao Z H，Peng L，Liu K，Yang Y，Qiu R X，Yang S L，Wu C H，Jiang J H，Wang Y L，Tan W J，Wang H T，Li J. A highly efficient Cu/ZnOx/ZrO2 catalyst for selective CO2 hydrogenation to methanol［J］.Journal of Catalysis，2022，414：236.

［17］Lam E，Corral-Perez J J，Larmier K，Noh G，Wolf P，Comas-Vives A，Urakawa A，Coperet C. CO2 hydrogenation on Cu/Al2O3：role of the metal/support interface in driving activity and selectivity of a bifunctional catalyst［J］.Angewandte Chemie，International Edition in English，2019，58（39）：13989.

［18］Shen C Y，Sun K H，Zhang Z T，Rui N，Jia X Y，Mei D H，Liu C J. Highly active Ir/In2O3 catalysts for selective hydrogenation of CO2 to methanol：experimental and theoretical studies［J］.ACS Catalysis，2021，11（7）：4036.

［19］Albukhari S M，Ismail A A. Highly dispersed Pt nanoparticle-doped mesoporous ZnO photocatalysts for promoting photoconversion of CO2 to methanol［J］.ACS Omega，2021，6（36）：23378.

［20］Schwiderowski P，Ruland H，Muhler M. Current developments in CO2 hydrogenation towards methanol：a review related to industrial application［J］.Current Opinion in Green and Sustainable Chemistry，2022，38：100688.

［21］（谢锋，杨志伟，王伟，白云龙，董凯伟. 黄金矿山含氰废水净化与回收工艺研究进展［J］.黄金，2023，44（4）：80.）

F Xie，Z W Yang，W Wang， Y L Bai，K W Dong. Research progress of gold mine cyanide wastewater purification and recycling process［J］.GOLD，2023，44（4）：80.

［22］Rui N，Wang Z Y，Sun K H，Ye J Y，Ge Q F，Liu C J. CO2 hydrogenation to methanol over Pd/In2O3：effects of Pd and oxygen vacancy［J］.Applied Catalysis B：Environmental，2017，218：488.

［23］Jiang F，Wang S S，Liu B，Liu J，Wang L，Xiao Y，Xu Y B，Liu X H. Insights into the influence of CeO2 crystal facet on CO2 hydrogenation to methanol over Pd/CeO2 catalysts［J］.ACS Catalysis，2020，10（19）：11493.

［24］Koizumi N，Jiang X，Kugai J，Song C S. Effects of mesoporous silica supports and alkaline promoters on activity of Pd catalysts in CO2 hydrogenation for methanol synthesis［J］.Catalysis Today，2012，194（1）：16.

［25］Sharma S K，Paul B，Srivastava A，Pal R S，Poddar M K，Khan T S，Samanta C，Bal R. The role of MgO during CO2 hydrogenation to methanol over Pd/ZnO catalyst［J］.Sustainable Chemistry for Climate Action，2023，2：100019.

［26］Collins S E，Baltanas M A，Bonivardi A L. An infrared study of the intermediates of methanol synthesis from carbon dioxide over Pd/β-Ga2O3［J］.Journal of Catalysis，2004，226（2）：410.

［27］Kong H，Li H Y，Lin G D，Zhang H B. Pd-decorated CNT-promoted Pd-Ga2O3 catalyst for hydrogenation of CO2 to methanol［J］.Catalysis Letters，2011，141（6）：886.

［28］Pothu R，Mitta H，Banerjee P，Boddula R，Srivastava R K，Kalambate P K，Naik R，Bahgat Radwan A，Al-Qahtani N. Insights into the influence of Pd loading on CeO2 catalysts for CO2 hydrogenation to methanol［J］.Materials Science for Energy Technologies，2023，6：484.

［29］（史琦，汪礼敏，纪永军，王立根，苏发兵，白帅. 金属单原子催化剂的制备及其电催化应用进展［J］.稀有金属，2023，47（8）：1132.）

Q Shi，L M Wang，Y J Ji，L G Wang，F B Su，S Bai. Recent advances in synthesis of single-atom metal catalysts and their electrochemical applications［J］.Chinese Journal of Rare Metals，2023，47（8）：1132.

［30］Xu J H，Su X，Liu X Y，Pan X L，Pei G X，Huang Y Q，Wang X D，Zhang T，Geng H R. Methanol synthesis from CO2 and H2 over Pd/ZnO/Al2O3：catalyst structure dependence of methanol selectivity［J］.Applied Catalysis A：General，2016，514：51.

［31］Bahruji H，Bowker M，Hutchings G，Dimitratos N，Wells P，Gibson E，Jones W，Brookes C，Morgan D，Lalev G. Pd/ZnO catalysts for direct CO2 hydrogenation to methanol［J］.Journal of Catalysis，2016，343：133.

［32］Bahruji H，Bowker M，Jones W，Hayward J，Ruiz Esquius J，Morgan D J，Hutchings G J. PdZn catalysts for CO2 hydrogenation to methanol using chemical vapour impregnation （CVI）［J］.Faraday discussions，2017，197：309.

［33］（裴启飞，郭孟伟，邵伟春，王恩泽，高明远，张启波. 锌电积体系Zn-MnO2同槽电解电化学分析［J］.有色金属科学与工程，2024，15（3）：322.）

Q F Pei，M W Guo，W C Shao，E Z Wang，M Y Gao，Q B Zhang. Electrochemical analysis of the simultaneous electrolysis of zinc and manganese dioxide in zinc electrowinning system［J］.Nonferrous Metals Science and Engineering，2024，15（3）：322.

［34］Collins S E，Chiavassa D L，Bonivardi A L，Baltanás M A. Hydrogen spillover in Ga2O3-Pd/SiO2 catalysts for methanol synthesis from CO2/H2［J］.Catalysis Letters，2005，103（1）：83.

［35］Gai L G，Jiang H H，Tian Y，Cui D L，Wang Q L. Low-temperature synthesis of β-Ga2O3 nanorods on SBA-15 microparticles by solvothermal method［J］.Nanotechnology，2006，17（23）：5858.

［36］Chiavassa D L，Collins S E，Bonivardi A L，Baltanás M A. Methanol synthesis from CO2/H2 using Ga2O3-Pd/silica catalysts：kinetic modeling［J］.Chemical Engineering Journal，2009，150（1）：204.

［37］Collins S E，Delgado J J，Mira C，Calvino J J，Bernal S，Chiavassa D L，Baltanás M A，Bonivardi A L. The role of Pd-Ga bimetallic particles in the bifunctional mechanism of selective methanol synthesis via CO2 hydrogenation on a Pd/Ga2O3 catalyst［J］.Journal of Catalysis，2012，292：90.

［38］Haghofer A，Föttinger K，Nachtegaal M，Armbrüster M，Rupprechter G. Microstructural changes of supported intermetallic nanoparticles under reductive and oxidative conditions：an in-situ X-ray absorption study of Pd/Ga2O3［J］.The Journal of Physical Chemistry C，2012，116（41）：21816.

［39］Rameshan C，Lorenz H，Armbrüster M，Kasatkin I，Klötzer B，Götsch T，Ploner K，Penner S. Impregnated and Co-precipitated Pd-Ga2O3，Pd-In2O3 and Pd-Ga2O3-In2O3 catalysts：influence of the microstructure on the CO2 selectivity in methanol steam reforming［J］.Catalysis Letters，2018，148（10）：3062.

［40］（杜一浩，霍腾飞，齐昱，李卓益，李云云，李雪礼，张琰图. 基于La2O3/Nd2O3纳米材料的催化发光丙酮传感器［J］.分析试验室，2024，43（10）：1391.）

Y H Du，T F Huo，Y Qi，Z Y Li，Y Y Li，X L Li，Y T Zhang. Cataluminescence acetone sensors based on La2O3/Nd2O3 nanomaterials［J］.Chinese Journal of Analysis Laboratory，2024，43（10）：1391.

［41］Kauppinen M，Posada-Borbón A，Grönbeck H. Methanol synthesis over PdIn，In2O3，and CuZn from first-principles microkinetics：similarities and differences［J］.The Journal of Physical Chemistry C，2022，126（36）：15235.

［42］Pinheiro Araujo T，Mondelli C，Agrachev M，Zou T，Willi P O，Engel K M，Grass R N，Stark W J，Safonova O V，Jeschke G，Mitchell S，Perez-Ramirez J. Flame-made ternary Pd-In2O3-ZrO2 catalyst with enhanced oxygen vacancy generation for CO2 hydrogenation to methanol［J］.Nature Communications，2022，13（1）：5610.

［43］Song J M，Liu S H，Yang C S，Wang G S，Tian H，Zhao Z J，Mu R T，Gong J L. The role of Al doping in Pd/ZnO catalyst for CO2 hydrogenation to methanol［J］.Applied Catalysis B：Environmental，2020，263：118367.

［44］（董春法，刘元发，寇勇勇，付锐平，肖新华，熊力，陈峥淏. 液相还原法制备单分散纳米金与纳米银颗粒［J］.有色金属工程，2023，13（11）：56.）

C F Dong，Y F Liu，Y Y Kou， R P Fu，X H Xiao，L Xiong，Z H Chen.Preparation of monodisperse gold and silver nanoparticles by liquid phase reduction method［J］.Nonferrous Metals Engineering，2023，13（11）：56.

［45］Quilis C，Mota N，Pawelec B，Millán E，Navarro Yerga R M. Intermetallic PdZn/TiO2 catalysts for methanol production from CO2 hydrogenation：the effect of ZnO loading on PdZn-ZnO sites and its influence on activity［J］.Applied Catalysis B：Environmental，2023，321：122064.

［46］Lawes N，Gow I E，Smith L R，Aggett K J，Hayward J S，Kabalan L，Logsdail A J，Slater T J A，Dearg M，Morgan D J，Dummer N F，Taylor S H，Bowker M，Catlow C R A，Hutchings G J. Methanol synthesis from CO2 and H2 using supported Pd alloy catalysts［J］.Faraday Discussions，2023，242：193.

［47］Lee D，Lee J Y，Lee J S. Effects of palladium particle size in hydrogenation of carbon dioxide to methanol over Pd/ZnO catalysts［J］.Studies in Surface Science and Catalysis，2004，153：169.

［48］Bowker M，Lawes N，Gow I，Hayward J，Esquius J R，Richards N，Smith L R，Slater T J A，Davies T E，Dummer N F，Kabalan L，Logsdail A，Catlow R C，Taylor S，Hutchings G J. The critical role of βPdZn Alloy in Pd/ZnO catalysts for the hydrogenation of carbon dioxide to methanol［J］.ACS Catalysis，2022，12（9）：5371.

［49］Li L D，Zhang B S，Kunkes E，Föttinger K，Armbrüster M，Su D S，Wei W，Schlögl R，Behrens M. Ga‐Pd/Ga2O3 catalysts：the role of gallia polymorphs，intermetallic compounds，and pretreatment conditions on selectivity and stability in different reactions［J］.ChemCatChem，2012，4（11）：1764.

［50］Qu J，Zhou X W，Xu F，Gong X Q，Tsang S C E. Shape effect of Pd-promoted Ga2O3 nanocatalysts for methanol synthesis by CO2 hydrogenation［J］.The Journal of Physical Chemistry C，2014，118（42）：24452.

［51］Oyola-Rivera O，Baltanás M A，Cardona-Martínez N. CO2 hydrogenation to methanol and dimethyl ether by Pd-Pd2Ga catalysts supported over Ga2O3 polymorphs［J］.Journal of CO2 Utilization，2015，9：8.

［52］Nikolaev V I，Maslov V，Stepanov S I，Pechnikov A I，Krymov V，Nikitina I P，Guzilova L I，Bougrov V E，Romanov A E. Growth and characterization of β-Ga2O3 crystals［J］.Journal of Crystal Growth，2017，457：132.

［53］Docherty S R，Phongprueksathat N，Lam E，Noh G，Safonova O V，Urakawa A，Coperet C. Silica-supported PdGa nanoparticles：metal synergy for highly active and selective CO2-to-CH3OH hydrogenation［J］.JACS Au，2021，1（4）：450.

［54］Tian G F，Wu Y Q，Wu S Y，Huang S，Gao J S. CO2 hydrogenation to methanol over Pd/MnO/In2O3 catalyst［J］.Journal of Environmental Chemical Engineering，2022，10（1）：106965.

［55］Li Z P，Men Y，Liu S，Wang J G，Qin K Y，Tian D D，Shi T L，Zhang L，An W. Boosting CO2 hydrogenation efficiency for methanol synthesis over Pd/In2O3/ZrO2 catalysts by crystalline phase effect［J］.Applied Surface Science，2022，603：154420.

［56］Araújo T P，Morales-Vidal J，Giannakakis G，Mondelli C，Eliasson H，Erni R，Stewart J，Mitchell S，Lopez N，Perez-Ramirez J. Reaction-induced metal-metal oxide interactions in Pd-In2O3/ZrO2 catalysts drive selective and stable CO2 hydrogenation to methanol［J］.Angewandte Chemie，International Edition in English，2023，62（42）：e202306563.

［57］Schiaroli N，Negahdar L，Lützen M，Hoang Ho P，Allen L J，Natoli A，Ospitali F，Maluta F，Rodríguez-Castellón E，Damsgaard C D，Fornasari G，Beale A M，Benito P. Efficient low-loaded ternary Pd-In2O3-Al2O3 catalysts for methanol production［J］.Journal of Catalysis，2023，424：140.

［58］García-Trenco A，Regoutz A，White E R，Payne D J，Shaffer M S P，Williams C K. PdIn intermetallic nanoparticles for the hydrogenation of CO2 to methanol［J］.Applied Catalysis B：Environmental，2018，220：9.

［59］Snider J L，Streibel V，Hubert M A，Choksi T S，Valle E，Upham D C，Schumann J，Duyar M S，Gallo A，Abild-Pedersen F，Jaramillo T F. Revealing the synergy between oxide and alloy phases on the performance of bimetallic In-Pd catalysts for CO2 hydrogenation to methanol［J］.ACS Catalysis，2019，9（4）：3399.

［60］Lin F W，Jiang X，Boreriboon N，Song C S，Wang Z H，Cen K F. CO2 hydrogenation to methanol over bimetallic Pd-Cu catalysts supported on TiO2-CeO2 and TiO2-ZrO2［J］.Catalysis Today，2021，371：150.

［61］Pan H X，Ma B R，Zhou L H，Hu Y F，Shakouri M，Guo Y，Liu X H，Wang Y Q. Highly efficient CuPd0.1/γ-Al2O3 catalyst with isolated Pd species for CO2 hydrogenation to methanol［J］.ACS Sustainable Chemistry & Engineering，2023，11（19）：7489.

［62］Han A Z，Ding J，Zhong Q. Role of single-atom Pd in Cu/ZrO2 catalysts for CO2 hydrogenation to methanol［J］.Colloids and Surfaces A：Physicochemical and Engineering Aspects，2022，641：128535.

［63］Malik A S，Zaman S F，Al-Zahrani A A，Daous M A，Driss H，Petrov L A. Selective hydrogenation of CO2 to CH3OH and in-depth DRIFT analysis for PdZn/ZrO2 and CaPdZn/ZrO2 catalysts［J］.Catalysis Today，2020，357：573.

［64］Lee K，Mendes P C D，Jeon H，Song Y Z，Dickieson M P，Anjum U，Chen L W，Yang T C，Yang C M，Choi M，Kozlov S M，Yan N. Engineering nanoscale H supply chain to accelerate methanol synthesis on ZnZrOx［J］.Nature Communications，2023，14（1）：819.

［65］García-Trenco A，White E R，Regoutz A，Payne D J，Shaffer M S P，Williams C K. Pd2Ga-based colloids as highly active catalysts for the hydrogenation of CO2 to methanol［J］.ACS Catalysis，2017，7（2）：1186.

［66］Lee K，Anjum U，Araújo T P，Mondelli C，He Q，Furukawa S，Pérez-Ramírez J，Kozlov S M，Yan N. Atomic Pd-promoted ZnZrO solid solution catalyst for CO2 hydrogenation to methanol［J］.Applied Catalysis B：Environmental，2022，304：120994.

［67］Xu Y M，Ding Z L，Qiu R，Hou R J. Effect of support and reduction temperature in the hydrogenation of CO2 over the Cu-Pd bimetallic catalyst with high Cu/Pd ratio［J］.International Journal of Hydrogen Energy，2022，47（65）：27973.

［68］Fiordaliso E M，Sharafutdinov I，Carvalho H W P，Grunwaldt J D，Hansen T W，Chorkendorff I，Wagner J B，Damsgaard C D. Intermetallic GaPd2 nanoparticles on SiO2 for low-pressure CO2 hydrogenation to methanol：catalytic performance and in-situ characterization［J］.ACS Catalysis，2015，5（10）：5827.

［69］Díez-Ramírez J，Díaz J A，Sánchez P，Dorado F. Optimization of the Pd/Cu ratio in Pd-Cu-Zn/SiC catalysts for the CO2 hydrogenation to methanol at atmospheric pressure［J］.Journal of CO2 Utilization，2017，22：71.

［70］Lin F W，Jiang X，Boreriboon N，Wang Z H，Song C S，Cen K F. Effects of supports on bimetallic Pd-Cu catalysts for CO2 hydrogenation to methanol［J］.Applied Catalysis A：General，2019，585：117210.

Basic Information:

DOI：10.13373/j.cnki.cjrm.XY23090009

Chinese Library Classification Number:O643

Citation Information:

The dangers posed by global warming and climate change have spurred scientists to intensify efforts in developing economically efficient methods to reduce atmospheric carbon dioxide （CO₂） accumulation. One particularly promising approach is catalytic conversion of CO₂ to methanol （CH₃OH） using renewable energy sources. This method not only mitigates CO₂ emissions but also plays a pivotal role in hydrogen storage and release processes，potentially driving advancements in the chemical and energy sectors. Such technology could promote more sustainable resource utilization，aligning with the dual objectives of environmental protection and sustainable development. Palladium （Pd）-based heterogeneous catalysts have emerged as prominent subjects of study in the realm of hydrogenation catalysis due to their exceptional hydrogen adsorption capabilities and impressive resistance to deactivation. In the domain of CO₂ hydrogenation to methanol，monometallic Pd catalysts are critical focal points of research due to their significant value and potential impact. These catalysts typically consist of active monometallic Pd supported on specific carriers，such as CeO₂，SiO₂，ZnO，and Ga₂O₃. These oxide carriers serve as support materials，providing a foundation for the dispersion of active metal Pd and fostering strong metal-oxide carrier interactions （SMSI）. This interaction significantly influencs the dispersion of active metal Pd and the formation of metal-carrier interface sites，both of which play crucial roles in the rate and selectivity of catalytic reactions. CeO₂，functioning as a catalyst carrier，prossesses remarkable CO₂ adsorption capacity and oxygen mobility. For instance，rod-like structures of CeO₂ （CeO₂-R） exhibit higher oxygen vacancy density and quantity，as well as enhanced oxygen mobility in CO₂ hydrogenation to methanol. By introducing an appropriate amount of Pd，CeO₂-R could enhance CO₂ reactivity and increase methanol yield. Using high-surface-area mesoporous SiO₂ support materials like MCM-41 and SBA-15 is beneficial in terms of improving the catalytic performance of CO₂ hydrogenation to methanol by facilitating the better dispersion of Pd nanoparticles. Additionally，the addition of alkaline promoters like Ca significantly increases the activity and selectivity of Pd catalysts. ZnO，serving as a carrier，could promote Pd particle dispersion and stability，consequently enhancing catalytic activity. The addition of MgO as a promoter could bolster reducibility of Pd catalysts，leading to improve activity and methanol selectivity in CO₂ hydrogenation. Similarly，Ga₂O₃ as a carrier also plays a pivotal function in CO₂ hydrogenation reactions. Through in-situ fourier-transform infrared spectroscopy （FT-IR） studies，it was revealed that Pd/β-Ga₂O₃ catalysts effectively convert CO₂ into for mate intermediates，which were subsequently hydrogenated to methanol，demonstrating outstanding selectivity. Despite advancements with monometallic Pd catalysts for CO₂ hydrogenation to methanol，they still face significant challenges related to activity，product selectivity，and catalyst stability. Therefore，researchers actively explored bimetallic catalysts as a strategy to enhance catalytic performance. By introducing metal oxides such as ZnO，Ga₂O₃，and In₂O₃ to form PdZn，PdGa，and PdIn alloys or metal intermetallic compounds，catalyst performance could be enhanced. These alloying processes could alter the chemical properties of the metal surface，provide new active sites，increase the metal surface area，and induce defect effects，thereby promoting CO₂ adsorption and activation，as well as methanol synthesis. In the case of PdZn alloy，ZnO formed PdZn alloys with Pd，increasing metal surface area and catalytic activity. Pd particles of varying sizes displayed distinct SMSI effects on ZnO carriers. Larger Pd particles showcased a stronger SMSI with ZnO carrier，enhancing both catalyst activity and methanol selectivity. Doping ZnO with Pd to create PdZn alloy catalysts significantly improved CO₂ hydrogenation to methanol efficiency，particularly on TiO₂ and Al₂O₃ carriers where PdZn catalysts performed exceptionally well. The addition of Ga₂O₃ promoted the formation of PdGa alloys，aiding in enhanced methanol selectivity. Pd-modified carriers like carbon nanotubes （CNT），promoted strong interactions between Pd and Ga₂O₃，resulting in the formation of PdGa alloys，thus enhancing methanol synthesis activity. Ga-doped SiO₂ carriers effectively suppressed the reverse water-gas shift （RWGS） reaction while improving CO₂ hydrogenation selectivity. PdIn alloys and intermetallic compounds also exhibited excellent catalytic performance. By introducing In₂O₃ to Pd catalysts to form PdIn alloys，catalysts' adsorption，CO₂ activation，and C-O bond cleavage capabilities could be enhanced. Furthermore，other bimetallic alloys like Pd-Cu alloys showed promising catalytic performance on various carriers，demonstrating high methanol selectivity and yield. The formation of alloy catalysts promoted H₂ dissociation and methanol production，enhancing CO₂ hydrogenation efficiency. By controlling oxide carriers，optimizing active sites，and improving metal-carrier interactions to form alloys or intermetallic compounds，catalytic performance in CO₂ hydrogenation to methanol reactions could be effectively enhanced. The development of monometallic Pd catalysts supported on specific carriers，such as CeO₂，SiO₂，ZnO，and Ga₂O₃，harnessed the unique properties of these support materials，including CO₂ adsorption and oxygen migration capabilities，to enhance the catalytic process. Despite some progress in monometallic Pd catalysts，significant challenges still remained，including activity，selectivity，and stability. To address these challenges，scientists investigated bimetallic catalysts，where Pd was combined with metal oxides to form alloys or intermetallic compounds. These bimetallic catalysts，through alterations in the chemical properties of the metal surface，the provision of new active sites，and the increase in metal surface area，exhibited enhanced performance. Research on Pd catalysts for CO₂ hydrogenation to methanol held immense potential for advancing the goals of mitigating climate change and developing sustainable energy sources. The insights gained from these studies were crucial for the ongoing optimization of catalyst design and its industrial application.