Confined Ni nanoparticles in N-doped carbon nanotubes for excellent pH-universal industrial-level electrocatalytic CO2 reduction and Zn-CO2 battery
Meiyin Li, Jigang Wang, Xuzi Cong, Yinggang Sun, Qiang Liu, Zhichao Miao, Zhongfang Li, Likai Wang
Abstract
Electrocatalytic reduction of CO 2 (ECR) offers a promising approach to curbed carbon emissions and complete carbon cycles. However, the inevitable creation of carbonates and limited CO 2 utilization efficiency in neutral or alkaline electrolytes result in low energy efficiency, carbon losses and its widespread commercial utilization. The advancement of CO 2 reduction under acidic conditions offers a promising approach for their commercial utilization, but the inhibition of hydrogen evolution reaction and the corrosion of catalysts are still challenging. Herein, Ni nanoparticles (NPs) wrapped in N -doped carbon nanotubes (Ni x NC-a) are successfully prepared by a facile mixed-heating and freeze-drying method. Ni 100 NC-a achieves a high Faraday efficiency (FE) of near 100 % for CO under pH-universal conditions, coupled with a promising current density of CO (>100 mA cm −2 ). Especially in acidic conditions, Ni 100 NC-a exhibits an exceptional ECR performance with the high FE CO of 97.4 % at −1.44 V and the turnover frequency (TOF) of 11 k h −1 at −1.74 V with a current density of 288.24 mA cm −2 . This excellent performance is attributed to the synergistic effect of Ni NPs and N -doped carbon shells, which protects Ni NPs from etching, promotes CO 2 adsorption and regulates local pH. Moreover, Ni 100 NC-a could drive the reversible Zn-CO 2 battery with a high power-density of 4.68 mW cm −2 and a superior stability (98 h). This study presents a promising candidate for efficient pH-universal CO 2 electroreduction and Zn-CO 2 battery.