Low Qi Hang, Loo Nicholas Wei Xian, Calle-Vallejo Federico, Yeo Boon Siang
Department of Chemistry, Faculty of Science, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore.
Solar Energy Research Institute of Singapore, SERIS, National University of Singapore (NUS), 7 Engineering Drive 1, Building E3A, #06-01, Singapore, 117574, Singapore.
Angew Chem Int Ed Engl. 2019 Feb 18;58(8):2256-2260. doi: 10.1002/anie.201810991. Epub 2019 Jan 29.
The electrocatalytic CO reduction reaction (CO RR) can dynamise the carbon cycle by lowering anthropogenic CO emissions and sustainably producing valuable fuels and chemical feedstocks. Methanol is arguably the most desirable C product of CO RR, although it typically forms in negligible amounts. In our search for efficient methanol-producing CO RR catalysts, we have engineered Ag-Zn catalysts by pulse-depositing Zn dendrites onto Ag foams (PD-Zn/Ag foam). By themselves, Zn and Ag cannot effectively reduce CO to CH OH, while their alloys produce CH OH with Faradaic efficiencies of approximately 1 %. Interestingly, with nanostructuring PD-Zn/Ag foam reduces CO to CH OH with Faradaic efficiency and current density values reaching as high as 10.5 % and -2.7 mA cm , respectively. Control experiments and DFT calculations pinpoint strained undercoordinated Zn atoms as the active sites for CO RR to CH OH in a reaction pathway mediated by adsorbed CO and formaldehyde. Surprisingly, the stability of the *CHO intermediate does not influence the activity.
电催化CO还原反应（CO RR）可以通过降低人为CO排放并可持续地生产有价值的燃料和化学原料来推动碳循环。甲醇可以说是CO RR最理想的含碳产物，尽管其生成量通常微不足道。在寻找高效的甲醇生产CO RR催化剂的过程中，我们通过将锌树枝晶脉冲沉积到泡沫银上（PD-Zn/泡沫银）来设计Ag-Zn催化剂。单独的锌和银无法有效地将CO还原为CH₃OH，而它们的合金生成CH₃OH的法拉第效率约为1%。有趣的是，通过纳米结构化，PD-Zn/泡沫银将CO还原为CH₃OH的法拉第效率和电流密度值分别高达10.5%和-2.7 mA cm⁻²。对照实验和DFT计算指出，在由吸附的CO和甲醛介导的反应途径中，应变低配位的锌原子是CO RR生成CH₃OH的活性位点。令人惊讶的是，*CHO中间体的稳定性并不影响活性。
