Atomically Defined Undercoordinated Active Sites for Highly Efficient CO2 Electroreduction
Atomically Defined Undercoordinated Active Sites for Highly Efficient CO2 Electroreduction
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DOI：
10.1002/adfm.201907658
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发表时间：
2019-11
影响因子：
19
通讯作者：
Wanzhen Zheng;Jian Yang;Hengquan Chen;Yang Hou;Qi Wang;Meng Gu;Feng He;Ying-qing Xia;
中科院分区：
文献类型：
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作者：
Wanzhen Zheng;Jian Yang;Hengquan Chen;Yang Hou;Qi Wang;Meng Gu;Feng He;Ying-qing Xia;
可充电Zn-CO2电池中电催化还原二氧化碳（CO2ER）仍然是一个巨大的挑战。在此，报道了一种高效CO2ER电催化剂，由配位不饱和单原子铜与锚定在石墨烯基质中的氮位点组成（Cu-N2/GN）。受益于不饱和配位环境和原子分散，超薄Cu-N2/GN纳米片表现出高CO2ER活性和对CO生成的选择性，起始电位为-0.33 V，在-0.50 V的低电位下最大法拉第效率为81%，优于先前报道的原子分散的Cu-N锚定在碳材料上。实验结果表明，石墨烯骨架中存在高度暴露且原子分散的 Cu-N2 活性位点，其中 Cu 物质由两个 N 原子配位。理论计算表明，优化的Cu-N2位点捕获CO2的反应自由能促进了CO2分子在Cu-N2位点上的吸附；同时，Cu-N2位点的短键长加速了电子从Cu-N2位点到*CO2的转移，从而有效地提高了*COOH的生成和CO2ER性能。设计的带有 Cu-N2/GN 纳米片的可充电 Zn-CO2 电池可提供 0.6 mW cm−2 的峰值功率密度，并且电池的充电过程可由自然太阳能驱动。
Electrocatalytic reduction of carbon dioxide (CO2ER) in rechargeable Zn–CO2 battery still remains a great challenge. Herein, a highly efficient CO2ER electrocatalyst composed of coordinatively unsaturated single‐atom copper coordinated with nitrogen sites anchored into graphene matrix (Cu–N2/GN) is reported. Benefitting from the unsaturated coordination environment and atomic dispersion, the ultrathin Cu–N2/GN nanosheets exhibit a high CO2ER activity and selectivity for CO production with an onset potential of −0.33 V and the maximum Faradaic efficiency of 81% at a low potential of −0.50 V, superior to the previously reported atomically dispersed Cu–N anchored on carbon materials. Experimental results manifest the highly exposed and atomically dispersed Cu–N2 active sites in graphene framework where the Cu species are coordinated by two N atoms. Theoretical calculations demonstrate that the optimized reaction free energy for Cu–N2 sites to capture CO2 promote the adsorption of CO2 molecules on Cu–N2 sites; meanwhile, the short bond lengths of Cu–N2 sites accelerate the electron transfer from Cu–N2 sites to *CO2, thus efficiently boosting the *COOH generation and CO2ER performance. A designed rechargeable Zn–CO2 battery with Cu–N2/GN nanosheets deliver a peak power density of 0.6 mW cm−2, and the charge process of battery can be driven by natural solar energy.