Photothermal methane coupling into liquid fuels with hydrogen evolution over nanocatalysts based on layered double hydroxide (LDH)

Abstract

The increasing energy and environmental problems have made clean energy-driven catalysis a hot research topic. Methane is an earth-abundant raw material but difficult to be converted by thermochemical processes. It is of great significance to seek novel strategies to convert methane into high value chemicals. Herein, we synthesize a series of transition metal catalysts based on layered double hydroxide precursors which were used for photothermal methane nonoxidative coupling reactions. The strong photothermal and chemisorption effects of the derived transition metal nanostructures allow the efficient activation of methane molecules. Among them, alumina supported metallic Ni and NiCo-alloy catalysts show excellent methane nonoxidative coupling activities, achieved hydrogen production rates of 4816.53 µmol g-1 h-1 and 5130.9 µmol g-1 h-1, accompanied by liquid fuels production rates of 59.2 mg g-1 h-1 and 63 mg g-1 h-1, respectively. The findings, therefore, provide a new strategy for methane nonoxidative coupling driven by light energy at mild conditions.

In Situ High-Temperature Reaction-Induced Local Structural Dynamic Evolution of Single-Atom Pt on Oxide Support

“…Experimental data have shown that the evolution of active sites on the Pt 1 /MnO 2 occurs in the presence of CH 4 (Figure b). Therefore, it is necessary to reveal the evolution of active sites through CH 4 dissociation during DFT simulation. , The CH 4 dissociation process indicates that the barrier on Pt 1 /MnO 2 –R (0.92 eV) is lower than that on Pt 1 /MnO 2 (1.21 eV) because of the formation of OVs adjacent to Pt 1 . In the cleavage step of the C–H bond, the CH 4 transfers one H atom to the adjacent O atom. , As expected, after CH 4 is adsorbed on the surface of Pt 1 /MnO 2 , the H atom of CH 4 first generates a lattice hydroxyl with the neighboring lattice oxygen that is most easily activated, which coincides with our speculated OVs site.…”

“…Therefore, it is necessary to reveal the evolution of active sites through CH 4 dissociation during DFT simulation. 48,49 The CH 4 dissociation process indicates that the barrier on Pt 1 / MnO 2 −R (0.92 eV) is lower than that on Pt 1 /MnO 2 (1.21 eV) because of the formation of OVs adjacent to Pt 1 . In the cleavage step of the C−H bond, the CH 4 transfers one H atom to the adjacent O atom.…”

Advances in Photothermal Catalysis: Mechanisms, Materials, and Environmental Applications

“…It is known that the layered-double-hydroxide (LDH) materials developed by Zhang et al have attracted extensive attention for photocatalysis and photothermal catalysis. − They synthesized CoFe-based catalysts by H 2 reduction of CoFeAl LDH nanosheets at 300–700 °C . The reduction temperature was found crucial in the surface chemical composition and morphology of the catalysts.…”