Improved Charge Separation and CO₂ Affinity of In₂O₃ by K Doping with Accompanying Oxygen Vacancies for Boosted CO₂ Photoreduction

Abstract

The CO 2 photocatalytic conversion efficiency of the semiconductor photocatalyst is always inhibited by the sluggish charge transfer and undesirable CO 2 affinity. In this work, we prepare a series of K-doped In 2 O 3 catalysts with concomitant oxygen vacancies (O V ) via a hydrothermal method, followed by a low-temperature sintering treatment. Owing to the synergistic effect of K doping and O V , the charge separation and CO 2 affinity of In 2 O 3 are synchronously promoted. Particularly, when P/P 0 = 0.010, at room temperature, the CO 2 adsorption capacity of the optimal K-doped In 2 O 3 (KIO-3) is 2336 cm 3 •g −1 , reaching about 6000 times higher than that of In 2 O 3 (0.39 cm 3 •g −1 ). As a result, in the absence of a cocatalyst or sacrificial agent, KIO-3 exhibits a CO evolution rate of 3.97 μmol•g −1 •h −1 in a gas−solid reaction system, which is 7.6 times that of pristine In 2 O 3 (0.52 μmol•g −1 •h −1 ). This study provides a novel approach to the design and development of efficient photocatalysts for CO 2 conversion by element doping.

Construction of an In2O3/Bi2S3 Z-Scheme Heterojunction for Enhanced Photocatalytic CO2 Reduction

“…The photoinduced charge separation and transfer efficiency of photocatalysts affect the number of charges participating in the photocatalytic reaction, which is of great importance to the photocatalytic activity. , As shown in Figure a,b, IOBS-3 exhibits a remarkably better photocurrent density of transient photocurrent response curve and linear sweep voltammetry (LSV) curves than that of Bi 2 S 3 and In 2 O 3 , indicating the improved charge separation efficiency of IOBS-3. − In the electrochemical impedance spectroscopy (EIS) Nyquist plots (Figure c), IOBS-3 has a smaller arc radius to Bi 2 S 3 and In 2 O 3 , suggesting the higher charge transfer efficiency of IOBS-3 . In Figure S10, the PL and PLE intensities of IOBS-3 are significantly lower than In 2 O 3 , revealing the lower charge recombination rate of IOBS-3 .…”