Zipeng Zeng,Aya Gomaa Abdelkader Mohamed,Xiang Zhang,Yaobing Wang
Although metal–N-doped carbons are promising electrocatalysts for CO 2 -to-CO conversion due to their high conversion efficiency and current density, their commercial application is still challenging due to their narrow potential/current range. In general, a wide potential/current electrocatalyst is in high demand for industrial CO 2 electrocatalysis. Controllable strategy to tune N configurations toward pyridinic-enriched metal–N x active sites is attractive. The synergetic effect of the ability of pyridinic N to capture Lewis acidic CO 2 and the characteristics of Ni–N active sites to inhibit the hydrogen evolution reaction (HER) can achieve a wide potential window, which has high practical value. Herein, the well-chosen precursors resulting in a pyridinic-enriched Ni–N x site can selectively catalyze CO 2 toward CO generation in aqueous media with a high Faradaic efficiency (FE) of 100% with an overpotential of 680 mV. Continuous CO FE > 90% was recorded under a wide range of potentials without decay. Motivated by its practical characteristics in CO 2 electrocatalysts, a Zn–CO 2 battery is assembled achieving a CO 2 –CO conversion efficiency of more than 90% in a wide discharge current window. Therefore, the results highlight that pyridinic-enriched Ni–N x holds great promise as simultaneous CO-selective electrocatalyst by suitably tuning M–N configurations as new perspective strategy.
Excellent porosity and accessibility are key requirements during carbon-based materials design for energy conversion applications. Herein, a Ni-based porous supramolecular framework with graphite-like morphology (Ni-SOF) was rationally designed as a carbon precursor. Ultrathin carbon nanosheets dispersed with Ni nanoparticles and Ni-N x sites (Ni@NiN x -N-C) were obtained via in-situ exfoliation during pyrolysis. Due to the hetero-porous structure succeeding from Ni-SOF, the Ni@NiN x -N-C catalyst showed outstanding bifunctional oxygen electrocatalytic activity with a narrow gap of 0.69 V between potential to deliver 10 mA cm −2 oxygen evolution and half-wave potential of oxygen reduction reaction, which even surpassed the Pt/C + IrO 2 pair. Therefore, the corresponding zinc-air battery exhibited excellent power output and stability. The multiple Ni-based active sites, the unique 2D structure with a high graphitization degree and large specific surface area synergistically contributed to the excellent bifunctional electrocatalytic activity of Ni@NiN x -N-C. This work provided a novel viewpoint for the development of carbon-based electrocatalyst.
危险品化学品经营许可证（带存储）