Zhang Qi, Zhang Yanxing, Mao Jianfeng, Liu Junyu, Zhou Yue, Guay Daniel, Qiao Jinli
State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, College of Environmental Science and Engineering, Donghua University, 2999 Ren'min North Road, Shanghai, 201620, P.R. China.
School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, P.R. China.
ChemSusChem. 2019 Apr 5;12(7):1443-1450. doi: 10.1002/cssc.201802725. Epub 2019 Mar 12.
Sn-based electrocatalysts are promising for the electrochemical CO reduction reaction (CO2RR), but suffer from poor activity and selectivity. A hierarchical structure composed of ultrathin SnO nanosheets anchored on the surface of the commercial multiwalled carbon nanotubes (MWCNTs) is synthesized by a simple hydrothermal process. The electrocatalytic performance can be further tuned by functionalization of the MWCNTs with COOH, NH , and OH groups. Both SnO @MWCNTs-COOH and SnO @MWCNTs-NH show excellent catalytic activity for CO RR with nearly 100 % selectivity for C products (formate and CO). SnO @MWCNTs-COOH has favorable formate selectivity with a remarkably high faradaic efficiency (FE) of 77 % at -1.25 V versus standard hydrogen electrode (SHE) and a low overpotential of 246 mV. However, SnO @MWCNTs-NH manifests increased selectivity for CO with higher current density. Density functional theory calculations and experimental studies demonstrate that the interaction between Sn species and functional groups play an important role in the tuning of the catalytic activity and selectivity of these functionalized electrocatalysts. SnO @MWCNTs-COOH and SnO @MWCNTs-NH both effectively inhibit the hydrogen evolution reaction and prove stable without any significant degradation over 20 h of continuous electrolysis at -1.25 V versus SHE.
锡基电催化剂在电化学二氧化碳还原反应（CO₂RR）中具有潜力，但活性和选择性较差。通过简单的水热法合成了一种由超薄SnO纳米片锚定在商用多壁碳纳米管（MWCNTs）表面组成的分级结构。通过用COOH、NH₂和OH基团对MWCNTs进行功能化，可以进一步调节电催化性能。SnO₂@MWCNTs-COOH和SnO₂@MWCNTs-NH₂对CO₂RR均表现出优异的催化活性，对C产物（甲酸盐和CO）的选择性接近100%。SnO₂@MWCNTs-COOH具有良好的甲酸盐选择性，在相对于标准氢电极（SHE）为-1.25 V时，法拉第效率（FE）高达77%，过电位低至246 mV。然而，SnO₂@MWCNTs-NH₂对CO的选择性增加，电流密度更高。密度泛函理论计算和实验研究表明，Sn物种与官能团之间的相互作用在调节这些功能化电催化剂的催化活性和选择性方面起着重要作用。SnO₂@MWCNTs-COOH和SnO₂@MWCNTs-NH₂均有效抑制析氢反应，并在相对于SHE为-1.25 V的条件下连续电解20 h以上，证明具有稳定性，无明显降解。
