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Tandem catalysis presents a promising strategy to improve the selectivity toward multicarbon products in the electrocatalytic carbon dioxide reduction reaction (CO2RR). For CO2RR, CO is a critical intermediate for producing multicarbon products. However, the management of CO localization and CO diffusion remains underexplored despite its critical role. Herein, a 3D tandem catalyst electrode with silver nanoparticles (Ag NPs) is designed to generate CO as an intermediate product within a copper (Cu) nanoneedle array. Via this nanostructured design, CO2 forms C2+ products with a high Faradaic efficiency (FEC2+) of 64% in an H‐cell and 70% in a flow cell with a current density of 350 mA cm−2. These figures‐of‐merit are currently among the top literature reports. More importantly, in situ Raman spectroscopy and finite‐element method calculations are employed to elucidate the origins of enhanced selectivity. These approaches reveal the crucial role of prolonging the CO diffusion path length for improving CO utilization during CO2 conversion with tandem catalyst systems. The favorable CO2RR FEC2+ in two distinct environments (H‐cell and flow cell) further corroborates that this effect is not limited to a particular reactor environment. Overall, this study provides new insights for designing tandem catalysts for improved CO2RR selectivity to C2+ products. [ABSTRACT FROM AUTHOR]

The reduced graphene oxide dopped equaixial geometry TiO2 (rGO/egTiO2) composite as photocatalyst was synthesized hydrothermally with various mass ratios of tetrabutyl titanate. The photocatalyst is considered to be rGO/equaixial geometry TiO2 in terms of modifying the combined reduced graphene Oxide and TiO2. The rGO plays a vital role in rGO/egTiO2 composite as photocatalysts were analyzed in methylene blue (MB) and rhodamine B (RhB) photocatalytic degradation under UV and simulated solar light irradiation. This synthesized catalyst was characterized by various analytical techniques such as XPS, XRD, SEM, BET, and TEM. The rGO/egTiO2 composite exhibits enhanced photocatalytic performance with degradation rates of 97.5 and 97% on RhB and MB for 60 min under UV radiation respectively, while the degradation rate of 94 and 92 % was observed on the same dyes for 6 h under the simulated sunlight radiation. The enhanced photocatalytic performance of the rGO/egTiO2 composite under ultraviolet irradiation source was owing to a high separation efficiency of the photo-induced electron-hole pairs, while the photocatalytic performance under simulated sunlight radiation was due to the photosensitive and charge separator behavior of rGO. This offers us an excellent potential of significant photocatalytic activity for the removal of organic contaminants from wastewater. [ABSTRACT FROM AUTHOR]

Combining adsorption and photocatalysis is an effective strategy for degrading organic pollutants. Here, BiVO 4 @diatomite composite photocatalyst (BiVO 4 @diatomite CP) was prepared by hydrothermal synthesis from Bi(NO 3 ) 3 ·5H 2 O glycerin solution, NH 4 VO 3 solution and diatomite. BiVO 4 @diatomite/microcrystalline cellulose/PVB composite fibers (BiVO 4 @diatomite/MCC/PVBCFs) were prepared from BiVO 4 @diatomite CPs, microcrystalline cellulose (MCC) and PVB ethanol solution using the electrospinning method. BiVO 4 @diatomite/MCC/PVBCFs were then mixed with pulp fibers to prepare the visible light-responsive photocatalytic paper. BiVO 4 @diatomite CP with a BiVO 4 /diatomite ratio of 6:4 had good interface states and displayed good photocatalytic activity with 64.32% degradation of methylene blue (MB) after 4 h. A PVB ethanol solution (6%) was formulated with BiVO 4 @diatomite CP and MCC to provide an ethanol spinning solution (12% solid) to prepare BiVO 4 @diatomite/MCC/PVBCFs (3:3:4). The resulting fibers had smooth surfaces, compact structures and exhibited good photocatalytic activity (66.80% and 56.80% degradation of MB and formaldehyde (HCHO), respectively, after 4 h). Photocatalytic paper containing 18% BiVO 4 @diatomite/MCC/PVBCFs had good photocatalytic activity with 50.20% degradation of HCHO after 4 h. This paper also had good physical properties and has the potential to be used for the photocatalytic degradation of indoor air pollutants, such as HCHO., (Copyright © 2020 Elsevier Inc. All rights reserved.)