posted on 2022-02-10, 18:44authored byJinxi Chen, Xiaofei Wei, Rongming Cai, Jiazheng Ren, Min Ju, Xiaoqing Lu, Xia Long, Shihe Yang
The Cu/Zn ratio of the CuZn electrocatalyst
is known to influence
the selectivity of CO2RR, but questions remain open about
how microstructure, crystal phase, and oxidation state of the metal
ions change and interplay in the composition tuning process, which
need to be carefully addressed for rational catalyst design. Toward
this end, we designed and synthesized a series of CuZn-based aerogel
materials with controlled Cu/Zn ratios and systematically investigated
their effects on CO2RR catalysis. From both experimental
results and theoretical calculations, we found that the introduction
of Zn into Cu aerogel greatly promoted the production of CO primarily
due to the unfavorable adsorption energy of *H. Surprisingly, the
intake of trace Ni atoms further inhibited the H2 evolution
reaction on account of the strong pinning of both *H and H2O* on the Ni sites. Therefore, the as-formed CuZn-Ni aerogel exhibited
a much-improved catalytic activity and selectivity for CO generation
with FE(CO) increased to 80% from 60%. This work gives insights into
the surface adsorption–desorption characteristics underlying
the activity and selectivity of electrocatalysts, which is of general
importance for CO2RR.