Coupling bimetallic Ni-Fe catalysts and nanosecond pulsed plasma for synergistic low-temperature CO2 methanation

Abstract

Plasma-enabled catalysis has great potential for driving many challenging reactions under mild conditions upon balancing the energy input and elementary process at catalytic surface. However, the comprehensive research system and fundamental knowledge of plasma-catalysis interaction are still limited, and plasma catalysis requires plasma-specific catalysts which are not known. Here, the highly-adjustable pulsed power and nickel foam (NF) based catalysts Ni-Fex-Al1-x/NF synergistically enabled the high-performance plasma-enabled CO2 methanation in our study. In-situ optical diagnosis, zero-dimension kinetic modelling and in-line electrical measurements were used to obtain an integrated insights into the synergetic effect on electron-induced reaction and vibrational distributions and describe a panorama of plasma contributions. Concerning the electron donating effect and excellent reducibility induced by Fe doping, the Ni-Fe0.25-Al/NF with its matched Fe/Ni ratio exhibited the outstanding CO2 conversion rate (67.5%) and energy efficiency (57,823 μg/kJ) with outstanding CH4 selectivity (99%) at 231 °C, and side reactions for CO generation were completely inhibited. Collectively, the electron-induced vibrational excitations CO(v) and small-sized Ni-Fe active phases (<10 nm) are the essential factors for overcoming the catalytic energy barriers at plasma involved interfacial catalysis, contributing to the much lower activation temperature.