Electrochemical CO₂ reduction (ECR) is a sustainable method for obtaining syngas, which is largely desired for producing high energy-dense hydrocarbons and alcohols through the industrialized process. However, it is still a challenge to adjust the H₂/CO ratio in a wide range while holding a large current density. Guiding by the density functional theory (DFT) calculations, the electrocatalyst of N-doped carbon-encapsulated metallic Ni particles supported on reduced graphene oxide (Ni@N-C/rGO) is developed for ECR to tunable syngas. The quantitative Ni@N-C responses to the controllable catalytic activity of ECR to CO, while the rGO serves as both HER catalyst and support of Ni@N-C. The Ni@N-C/rGO material exhibits high CO₂ reduction activity and stability, thereby achieving a specific current of 23 mA cm^-2 and CO Faradaic efficiency (FE_(CO)%) of 90% at -0.97 V vs. RHE. More importantly, the H₂/CO ratio of the syngas can be adjusted in a large range of 9/1 to 1/9 without potential-dependence while maintaining large current densities (>15 mA cm^-2).

电化学还原CO ₂（ECR）是获得合成气的一种可持续方法，这对于通过工业化过程生产高能量密度的烃和醇是非常需要的。然而，在保持大电流密度的同时在宽范围内调节H ₂ / CO比仍然是挑战。以密度泛函理论（DFT）计算为指导，开发了负载在还原氧化石墨烯（Ni @ NC / rGO）上的N掺杂碳包裹的金属Ni粒子的电催化剂，用于可调谐合成气的ECR。Ni @ NC定量响应ECR对CO的可控催化活性，而rGO既是HER催化剂又是Ni @ NC的载体。Ni @ NC / rGO材料显示出高的CO ₂还原活性和稳定性，从而在相对于RHE的-0.97 V时实现23 mA cm ^-2的比电流和90％的CO法拉第效率（FE _（CO）％）。更重要地，合成气的H ₂ / CO比可在9/1至1/9的大范围内调节而无电位依赖性，同时保持大电流密度（> 15mA cm ^-2）。