Efficient catalysis and products regulation of methane dry reforming under mild temperature conditions using novel high-entropy catalyst

Abstract

Dry reforming of methane to syngas (H2/CO) is the most dominant upstream reaction in chemical production line, which also helps capture greenhouse gases. In this work, we report a novel CoxNi0.8-xLa0.2Ca0.5Ce0.5@Al2O3 high-entropy catalyst applied to CH4-CO2 reforming reaction, which can widen the reaction-temperature window and achieve over 40 % methane conversion and 220 mmol·gcat−1·h−1 hydrogen yield at 500 °C. Compared with other studies, the activity of proposed CoxNi0.8-xLa0.2Ca0.5Ce0.5@Al2O3 high-entropy catalyst exhibits absolute advantage in low-medium temperature environments (500–650 °C). Due to the regulation of structure–activity relationship among various active metal elements, the proposed catalysts present synergistic effect within catalytic system, which can also suppress carbon deposition and maintain stable activity during a 12-hour continuous operation. Importantly, this research utilizes the remarkable characteristics of high-entropy alloys to induce the orderly transformation of reactants. The thermodynamic regulation of the reaction process is also improved by regulating the catalyst structure and thermal properties through intermetallic lattice distortion and “Maximum Entropy Theory”. The experimental results show that the product H2/CO ratio can be stably maintained over 0.9 for temperature ranging from 500 to 850 °C. This provides a reference for the application of high-entropy alloys in the field of carbon capture and hydrogen production.