MOF-Templated Preparation of Highly Dispersed Co/Al₂O₃ Composite as the Photothermal Catalyst with High Solar-to-Fuel Efficiency for CO₂ Methanation

Abstract

CH4 production from CO2 hydrogenation provides a clean approach to convert greenhouse gas CO2 into chemical energy, but high energy consumption in this reaction still restrains its further application. Herein, we use a light-driven CO2 methanation process instead of traditional thermocatalysis by an electrical heating mode, with the aim of greatly decreasing the energy consumption. Under UV–vis–IR light irradiation, the photothermal CO2 methanation over highly dispersed Co nanoparticles supported on Al2O3 (Co/Al2O3) achieves impressive CH4 production rates (as high as 6036 μmol g–1 h–1), good CH4 selectivity (97.7%), and catalytic durability. The high light-harvesting property of the catalyst across the entire solar spectrum coupled with its strong adsorption capacity toward H2, CO2, CO, and abundant active sites are proposed to be responsible for the better photothermocatalytic performance of Co/Al2O3. Furthermore, a novel light-promotion effect is also revealed in CO2 methanation, where UV–vis light irradiation induces oxygen vacancies and improves the proclivity toward adsorption of H2, CO2, and CO, finally resulting in a significant enhancement of the photothermocatalytic activity for CH4 production. By concentrating the low-intensity light (120 mW/cm2) via a Fresnel lens, a photothermal CO2 conversion efficiency of more than 50% with a good CH4 selectivity (76%) is achieved on the optimal catalyst under a dynamic reaction system, which indicates the bright prospect of photothermal CO2 methanation.

Photothermal Chemistry Based on Solar Energy: From Synergistic Effects to Practical Applications

“…We have summarized a number of representative PTC works involving different fields, as shown in Table 1 . [ 33,36,38‐47,49‐57,61‐68,70‐73,75‐81,83,85,87‐89,94,111‐113,115,117,118,120,121,123‐168 ] The PTC works are categorized into three major fields, solar fuel production, chemical synthesis, and environmental remediation, and the catalysts and energy sources used in the studies, along with the reaction temperatures and reaction results are collected. Besides, the datasets of the temperatures and the reaction results have been extracted and plotted for better visibility, as shown in Figure .…”

“…According to plenty of PTC researches, benefits from non‐thermal effect usually involve 1) reducing the energy barriers, so that the initial reaction temperatures can be reduced, [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ] 2) promoting the activation of reactants and/or intermediate species, and thus accelerating the reaction rate, [ 36 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ] 3) adjusting the reaction paths, and changing the product selectivity, [ 42 , 49 , 50 , 51 , 52 , 53 , 54 ] and 4) desorbing harmful surface species or keeping the catalytic active sites (such as oxygen vacancy or low valence state) at a stable state to keep catalysts activated. [ 39 , 40 , 43 , 55 , 56 , 57 ]…”

“…We have summarized a number of representative PTC works involving different fields, as shown in Table 1 . [ 33 , 36 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 70 , 71 , 72 , 73 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 83 , 85 , 87 , 88 , 89 , 94 , 111 , 112 , 113 , 115 , 117 , 118 ...…”

“…We have summarized a number of representative PTC works involving different fields, as shown in Table 1. [33,36,[38][39][40][41][42][43][44][45][46][47][49][50][51][52][53][54][55][56][57][61][62][63][64][65][66][67][68][70][71][72][73][75][76][77][78][79][80][81]83,85,[87][88][89]94,[111][112][113]115,…”

An Efficient Metal–Organic Framework‐Derived Nickel Catalyst for the Light Driven Methanation of CO2

“…The catalyst exhibited CH 4 production rate of 6036 mmol g À1 h À1 and selectivity of 97.7 % after UV-vis-IR light irradiation. [18] Herein, we explore the MOF-mediated approach to synthesize highly dispersed Ni NPs supported on a carbon matrix derived from Ni-MOF-74. We demonstrate the outstanding catalytic performance of the Ni@C materials in the methanation reaction, achieving high conversion rates, selectivity and recyclability without any external heating.…”