Zn-Based nanowires for electrocatalytic reduction of CO2 to syngas

The electrochemical reduction of CO2 into CO has emerged as a strategically significant technology for mitigating the environmental impacts stemming from anthropogenic global warming while enabling the conversion of CO2 into energy resources. Syngas, a critical feedstock in the petroleum industry for synthesizing fuels and chemicals, is traditionally produced via coal gasification and natural gas reforming. However, against the backdrop of the gradual exhaustion of fossil energy reserves and escalating environmental exigencies, electrochemical CO2 reduction (CO2RR) coupled with water splitting has emerged as an ideal alternative route to produce syngas with tunable CO/H2 ratios. Zn, a crustally abundant element in the Earth’s crust, emerges as a viable and cost-effective substitute for noble metal-based electrocatalysts (e.g., Au, Ag) in CO2RR. The development of cost-competitive, highly catalytically active electrocatalysts is are critical prerequisites for mitigating atmospheric CO₂ accumulation and enhancing the valorization of CO₂RR products. Herein, through morphology regulation of an electrodeposited Zn‑based catalyst followed by solution‑phase reconstruction and thermal treatment, a nanowire‑structured Zn catalyst was fabricated. The catalyst exhibits remarkable performance for CO₂RR, demonstrating an ultra‑wide tunable CO/H2 ratio from 1.4 to 5.8 at potentials between −0.6 and −1.4 V vs. RHE. At −1.2 V vs. RHE, a stable CO/H₂ ratio of 3 was maintained continuously for 9 h. Furthermore, the influences of the KHCO3 electrolyte concentration on the catalytic performance of the Zn‑24h/H₂ catalyst was investigated. The result demonstrate that higher KHCO3 electrolyte concentrations can enhance the current density but the hydrogen evolution will be promoted, thus reduce CO selectivity, and narrow the tunable range of the CO/H2 ratio. By tailoring catalyst morphology and electrolyte concentration, the syngas composition can be effectively modulated. This study offers new possibilities for designing advanced catalytic system suitable for a variety of syngas‑based industrial applications.