Facile Synthesis of Hierarchically Porous Ni–N–C for Efficient CO₂ Electroreduction to CO

Abstract

The reasonable design of atomically dispersed Ni–N x sites in porous carbon nanostructures is an efficient strategy to enhance the electrochemical CO2 reduction reaction (CO2RR) catalytic activity. In this work, atomically dispersed Ni–N x sites on hierarchically porous carbon catalysts (HP-Ni-NC) were fabricated by a facile NaCl template-assisted pyrolysis method. The catalysts exhibit a large specific surface area and a hierarchical porous structure, facilitating the exposure of numerous active sites and the mass/electron transport during the CO2RR. Consequently, the CO Faradaic efficiency maintained over 90% in a wide potential window on the optimized HP-Ni-NC-2 catalyst. The CO partial current achieved 15.2 mA cm–2 at −0.9 V (vs reversible hydrogen electrode) in a H-cell. Furthermore, the current density can achieve 250 mA cm–2 at a cell voltage of 3.11 V in a membrane electrode assembly electrolyzer, demonstrating great promise for commercial-scale application. This study presents a facile approach to synthesizing hierarchically porous structure single-atom catalysts with superior catalytic performance toward CO2RR.

Boosting Electrochemical CO2 Reduction to CO by Regulating the Porous Structure of Carbon Membrane

“…The enhanced performance of the pore-structured carbon membrane electrodes primarily stems from the facilitation of the mass transport of CO 2 and the exposure of additional active sites. When compared to the powder electro-catalysts of Ni–N–C reported in recent literature (Table S4), ,,− our self-supported carbon membrane electrode K 0.66 -Ni-NC exhibited an exceptionally wide operational window (>900 mV), making it a promising candidate for CO 2 reduction applications. We inferred that this behavior was a distinct feature of nitrogen-doped carbon self-supported electrodes.…”

Size effect of nickel from nanoparticles to clusters to single atoms for electrochemical CO2 reduction

“…10,11 Despite significant efforts having been devoted to the design of nitrogen-doped-carbon-supported metal catalysts, the catalytic performance still needs to improve to meet the requirements for practical applications. 12,13 Therefore, it is urgent to develop low-cost and highly efficient catalysts for the CO 2 RR.…”