Creation of SnxNb1−xO2 solid solution through heavy Nb-doping in SnO2 to boost its photocatalytic CO2 reduction to C2+ products under simulated solar illumination

Abstract

Photocatalytic CO2 reduction driven by green solar energy could be a promising approach for the carbon neutral practice. In this work, a novel defect engineering approach was developed to form the SnxNb1−xO2 solid solution by the heavy substitutional Nb-doping of SnO2 through a robust hydrothermal process. The detailed analysis demonstrated that the heavy substitution of Sn4+ by a higher valence Nb5+ created a more suitable band structure, a better photogenerated charge carrier separation and transfer, and stronger CO2 adsorption due to the presence of abundant acid centers and excess electrons on its surface. Thus, the SnxNb1−xO2 solid solution sample demonstrated a much better photocatalytic CO2 reduction performance compared to the pristine SnO2 sample without the need for sacrificial agent. Its photocatalytic CO2 reduction efficiency reached ∼292.47 µmol/(g·h), which was 19 times that of the pristine SnO2 sample. Furthermore, its main photocatalytic CO2 reduction product was a more preferred multi-carbon (C2+) compound of C2H5OH, while that of the pristine SnO2 sample was a one-carbon (C1) compound of CH3OH. This work demonstrated that, the heavy doping of high valence cations in metal oxides to form solid solution may enhance the photocatalytic CO2 reduction and modulate its reduction process, to produce more C2+ products. This material design strategy could be readily applied to various material systems for the exploration of high-performance photocatalysts for the solar-driven CO2 reduction.

Advances in Modulating the Activity and Selectivity of Photocatalytic CO2 Reduction to Multicarbon Products

“…Metal ion doping has been widely researched to modify photocatalysts because metal ions may act as hole trappers to benefit the H 2 O oxidation process and provide large amounts of protons to form excessive specific C1 intermediates, which are beneficial for the C–C coupling. , In other words, the doping of metal ions can prompt the formation of C2+ products through altering the pathway of CO 2 photoreduction and thus regulate the selectivity of C2+ products. ,− …”

“…Metal ion doping has been widely researched to modify photocatalysts because metal ions may act as hole trappers to benefit the H 2 O oxidation process and provide large amounts of protons to form excessive specific C1 intermediates, which are beneficial for the C−C coupling. 49,68 In other words, the doping of metal ions can prompt the formation of C2+ products through altering the pathway of CO 2 photoreduction and thus regulate the selectivity of C2+ products. 49,68−70 For example, Li et al in situ prepared a porous cake-like TiO 2 photocatalyst with mixed anatase−rutile phase by using MIL-125(Ti) as both precursor and template and then doped Cu and Co successively into the obtained TiO 2 by a hightemperature calcination method.…”

Advances in Sno₂-Based Nanomaterials for Photocatalysis, Supercapacitors, and Antibacterial Activities

“…When the photodegradation efficiencies of ZnO-SnO2 were evaluated with binary and ternary dye mixes, they were comparable to those of the single mixtures, suggesting that this material may eventually be employed in commercial applications. Gao et al [125] demonstrated a photocatalytic CO2 reduction. In this study, a unique defect engineering method was developed to produce SnxNb1xO2 by a sustainable hydrothermal method that significantly substitutes Nb into SnO2.…”

3D/2D ZnIn2S4/BiFeO3 as S‐scheme heterojunction photocatalyst for boosted visible‐light hydrogen evolution

“…[7][8][9][10][11] However, the high charge recombination still restricts the photocatalytic H 2 evolution efficiency of photocatalyst, which cannot meet the high requirements of practical applications. [12][13][14] With this regard, semiconductor photocatalysts with various modification, including elemental doping, [15][16][17][18][19] heterojunction constructing, [20][21][22][23] morphology regulating, [24][25][26][27] were developed with a goal of attaining enhanced photocatalytic H 2 evolution for prospective industrialization.…”