Designing highly selective and energy-efficient electrocatalysts to minimize the competitive hydrogen evolution reaction in the electrochemical reduction of aqueous CO2 remains a challenge. In this study, we report that doping Pd with a small amount of Te could selectively convert CO2 to CO with a low overpotential. The PdTe/few-layer graphene (FLG) catalyst with a Pd/Te molar ratio of 1 : 0.05 displayed a maximum CO faradaic efficiency of about 90% at –0.8 V (vs. a reversible hydrogen electrode, RHE), CO partial current density of 4.4 mA cm–2, and CO formation turnover frequency of 0.14 s–1 at –1.0 V (vs. a RHE), which were 3.7-, 4.3-, and 10-fold higher than those of a Pd/FLG catalyst, respectively. Density functional calculations showed that Te adatoms preferentially bind at the terrace sites of Pd, thereby suppressing undesired hydrogen evolution, whereas CO2 adsorption and activation occurred on the high index sites of Pd to produce CO.
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机译：设计高选择性和高能效的电催化剂以最大程度地减少在电化学还原含水二氧化碳中的竞争性放氢反应仍然是一个挑战。在这项研究中，我们报告说，用少量Te掺杂Pd可以有选择地将CO2转化为低过电势的CO。 PdTe / Te摩尔比为1：0.05的PdTe /几层石墨烯（FLG）催化剂在–0.8 V时显示最大的CO法拉第效率（相对于可逆氢电极，RHE），CO分流密度为4.4 mA cm –2 ，在–1.0 V时CO形成转换频率为0.14 s -1 （相对于RHE），分别为3.7-，4.3-分别比Pd / FLG催化剂高10倍。密度泛函计算表明，Te原子优先结合在Pd的平台位上，从而抑制了不希望有的氢的释放，而CO2在Pd的高指数位上发生了吸附和活化，从而产生了CO。
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