Ni–Fe nanoparticles prepared using hydrotalcite precursors enhance the photocatalytic performance of CO2 methanation

Abstract

A series of Fe-modified bimetallic hydrotalcite-like photocatalysts are prepared through co-precipitation containing amounts of M2+(NO3)2·6H2O (M2+ = Mg, Ni) and M3+(NO3)3·9H2O (M3+ = Al, Fe) with a fixed Ni content and a monometallic 25Ni/Al2O3 catalyst for comparison purpose. The main objective of this experimental work is to study the replacement of Al with Fe in the photocatalyst on the CO2 methanation performance under three different reaction conditions (dark, ultraviolet and visible illumination). Thus, the use of Fe as a promoter has been studied for improving the light adsorption capability of photocatalysts and the reducibility of active metals. However, the results showed that modification by Fe acting as active metal and as support modification, is less effective than modification by Al. Therefore, the effects of both the basicity and photothermal activation by plasmonic nanoparticles under ultraviolet and visible photocatalytic conditions improve the methane production compared to the reaction under dark conditions.