Tip carbon encapsulation customizes cationic enrichment and valence stabilization for low K+ acidic CO2 electroreduction
Zhitong Wang, Dongyu Liu, Chenfeng Xia, Xiaodong Shi, Yansong Zhou, Qiuwen Liu, Jiangtao Huang, Haiyan Wu, Deyu Zhu, Shuyu Zhang, Jing Li, Peilin Deng, Andrey S. Vasenko, Bao Yu Xia, Xinlong Tian
Abstract
Abstract Acidic electrochemical CO 2 conversion is a promising alternative to overcome the low CO 2 utilization. However, over-reliance on highly concentrated K + to inhibit the hydrogen evolution reaction also causes (bi)carbonate precipitation to interfere with catalytic performance. In this work, under the screening and guidance of computational simulations, we present a carbon coated tip-like In 2 O 3 electrocatalyst for stable and efficient acidic CO 2 conversion to synthesize formic acid (HCOOH) with low K + concentration. The carbon layer protects the oxidized In species with higher intrinsic activity from reductive corrosion, and also peripherally formulates a tip-induced electric field to regulate the adverse H + attraction and desirable K + enrichment. In an acidic electrolyte at pH 0.94, only 0.1 M low K + is required to achieve a Faradaic efficiency (FE) of 98.9% at 300 mA cm −2 for HCOOH and a long-time stability of over100 h. By up-scaling the electrode into a 25 cm 2 electrolyzer setup, a total current of 7 A is recorded to sustain a durable HCOOH production of 291.6 mmol L −1 h −1 .