Fabrication of Black In2O3 with Dense Oxygen Vacancy through Dual Functional Carbon Doping for Enhancing Photothermal CO2 Hydrogenation

Abstract

Photothermocatalytic CO2 reduction as the channel of the energy and environmental issues resolution has captured persistent attention in recent years. In2O3 has been prompted to be a potential photothermal catalyst in this sector on account of unique physicochemical properties. However, different from the metal-based photothermal catalyst with the nature of efficient light-to-thermal conversion and H2 dissociation, the wide-bandgap semiconductor needs to be modified to possess wide-wavelength-range absorption and the active surface. It remains a challenge to achieve the two aims simultaneously via single material modulation approach. In this study, one strategy of carbon doping can empower In2O3 with two advantageous modifications. The carbon doping can reduce the formation energy of oxygen vacancy, which induces the generation of oxygen-vacancy-riched material. The introduction of oxygen defect levels and carbon doping levels in band gap of In2O3 significantly reduces this band gap, which endows it full-spectral and intensive solar light absorption. Therefore, the carbon doped In2O3 achieves effective light-to-thermal conversion and delivers a 123.6 mmol g− 1 h− 1 of CO generation rate with near-unity selectivity, as well as prominent stability in photothermocatalytic CO2 reduction.

Subsurface oxygen defects electronically interacting with active sites on In2O3 for enhanced photothermocatalytic CO2 reduction

“…They are made available for most of reactions involving photocatalysis, electrocatalysis, thermocatalysis, and photothermocatalysis. In recent years, applications of oxygen defects have made significant progress in CO 2 reduction [5][6][7] , CO oxidation [8][9][10] , and NH 3 synthesis [11][12][13] . But these previous studies focused on surface oxygen defects, especially increasing the density of active sites to enhance apparent catalytic activity, while the "quality" (namely, reactivity) of oxygen defects is usually neglected.…”

Carburized In2O3 Nanorods Endow CO2 Electroreduction to Formate at 1 A cm–2

“…As depicted in Figure i, the 3D Raman spectra scanning image proved the evenly distributed carbon atoms on the catalyst. By analyzing the data of XPS in Figure j, the In 3d peak at 444.1 eV (In 3d 3/2 ) and 451.7 eV (In 3d 5/2 ) of In 2 O 3 -C has a negative shift of 0.17 eV compared to In 2 O 3 , indicating that the electron density of In atoms was enriched due to the electron donor effect of carbon atoms. − …”

Direct photoconversion of CO2 to carbon nanotubes for oxygen recycling in extraterrestrial exploration

“…By converting CO2 to C, the Bosch process (overall reaction: 2H2 + CO2 → C + 2H2O) provides an alternative way to close the water loop, thereby permitting 100% theoretical oxygen recovery. However, the Bosch technology consists of multiple, complicated reactions, i.e., the reverse water-gas shift (RWGS, H2 + CO2 → CO + H2O) 12,13,14 , carbon monoxide hydrogenation (H2 + CO → C + H2O), and Boudouard reactions (2CO → C + CO2); the optimal operating temperatures and space velocities of these reactions vary from each other, making the Bosch system a complex, series reactor configuration in which each sub-reactor needs independent optimization. In addition, its low single-pass efficiency (for example ca.…”

“…1a). Isotope-labeled 13 CO2, instead of 12 CO2, was utilized as the feed gas (along with H2) to confirm the carbon source for CNT formation: 1) the Raman bands of 13 C CNTs shift to lower frequencies as compared to those of 12 C CNTs, consistent with theoretical prediction (Fig. 1b and Supplementary Information experimental procedures section) 23 ; 2) the released gas molecules during the whole combustion process of solid product (via a thermogravimetric analyzer, TGA) as monitored by mass spectrometry (MS) are mainly 13 CO2 (Figs.…”