Abstract:
Achieving carbon peak and carbon neutrality is a critical strategic requirement for China's green and sustainable development. Syngas, as a vital raw material for modern chemical production, traditionally relies heavily on fossil fuels for its preparation, resulting in significant greenhouse gas emissions. In recent years, the technology of electrocatalytic CO
2 reduction to syngas driven by renewable electricity has emerged as an environmentally friendly and sustainable alternative, garnering extensive research interest.While previous studies have explored the impact of different catalysts on the
V(H
2)/
V(CO) ratio in syngas produced via electrocatalytic CO
2 reduction, effectively tuning the selectivity of H
2 and CO using a single catalyst remains a challenge. To achieve selective modulation of the
V(H
2) /
V(CO) ratio in syngas products with a single catalyst, this study synthesized CuGa
2 intermetallic compounds through a high-temperature solid-state synthesis process. These compounds were employed as electrocatalysts to enable high selectivity and tunability in the electrocatalytic CO
2 reduction to syngas.A range of characterization techniques, including SEM, EDS, XRD, and XPS, were used to investigate the physicochemical properties and electrochemical performance of the CuGa
2 intermetallics, as well as their catalytic mechanisms during the electrocatalytic CO
2 reduction process. The results indicated that this catalyst, consisting of a mixture of CuGa
2 and a small amount of metal oxides, could significantly adjust its selectivity for the electrocatalytic CO
2 reduction reaction (eCO
2RR) and the hydrogen evolution reaction (HER) by varying electrolyte concentration and pH, thereby modulating the
V(H
2)/
V(CO) ratio in the syngas produced.Moreover, tests examining the impact of different applied potentials on the
V(H
2)/
V(CO) ratio demonstrated that controlling the applied potential allows for the adjustment of active site utilization in the CuGa
2 catalyst, thus altering the selectivity of both eCO2RR and HER. This enables the
V(H
2)/
V(CO) ratio in syngas products to be tuned within a range of 0.3 to 4.