Dual Hole Transport Layers Heterojunction and Band Alignment Engineered Mo:BiVO4 Photoanodes for Efficient Water Splitting.

BiVO4-based photoanode is one of the most promising photoanodes for photoelectrocatalytic water splitting. However, the serious problem of interface charge recombination limits its further development. Here, a Mo:BiVO4/NiOx/CPF-TCzB/NiCoBi photoanode is constructed with double hole transport layer and an energy level gradient to achieve an effective photo-generated holes extraction and accumulation at the surface electrocatalyst. The conjugated polycarbazole framework CPF-TCzB is used as hole transport layer to eliminate the charge recombination center between Mo:BiVO4 and NiCoBi electrocatalyst and realize the extraction and storage of photo-generated hole; NiOx nanoparticles are further inserted between Mo:BiVO4 and CPF-TCzB to form a gradient energy level, eliminating the energy level barrier and optimizing band alignment. As a result, Mo:BiVO4/NiOx/CPF-TCzB/NiCoBi achieves a much higher photocurrent densities of 3.14 mA cm-2 than that of Mo:BiVO4 (0.42 mA cm-2) at 0.6 V versus RHE. This work provides an specific way to adjust the band structure of BiVO4-based photoanodes and realize efficient hole extraction and storage for PEC water splitting.

Low cost and highly dispersed Ce/Na-ZSM-5 catalysts close to atomic dispersion for enhancing formaldehyde oxidation.

Formaldehyde oxidation at room temperature with low-cost catalysts is one of the main development directions of environmental governance. Herein, we developed a low-cost and superior performance highly dispersed Ce on Na-ZSM-5 (Ce/Na-ZSM-5) catalyst, which is close to atomic dispersion for indoor formaldehyde (HCHO) oxidation at low temperature. The highly dispersed catalyst that was similar to atomic dispersion was characterized by EXAFS and AC HAADF-STEM. The optimal Ce/Na-ZSM-5 displays high HCHO removal performance (95%, at room temperature), as well as 100 h stable testing (∼90% HCHO removal). In addition, a reasonable reaction mechanism of the HCHO catalytic oxidation is proposed based on the in situ DRIFT spectra and DFT calculation. This work provides a new way to design an efficient catalyst for the complete oxidation of formaldehyde.

Promoting Plasmonic Hot Hole Extraction and Photothermal Effect for the Oxygen Evolution Reactions.

Boosting oxygen evolution reaction by local surface plasmon resonance (LSPR) provides breakthrough opportunities for the promotion of solar energy conversion; the potential of LSPR, however, has rarely been tapped and investigated. Here, we report the precise regulation of commercial Au nanoparticles plasmonic nanomaterial and OER electrocatalysts, viz., the NiCoOx electrocatalytic layer with hole transport ability and photothermal effect is prepared on the surface of Au nanoparticles by photoelectrodeposition. The NiCoOx layer not only increases the transmission distance of holes generated by plasmonic Au nanoparticles, but also reduce the agglomeration of plasmonic Au nanoparticles during long-time OER reaction, which greatly improves the OER catalytic ability. The current density of NiCoOx /Au anode achieves 16.58 mA cm-2 at 2.0 V versus RHE, which is about 6.5 times of pristine NiCoOx anode (2.56 mA cm-2 ) and 47 times of pristine Au anode (0.35 mA cm-2 ). More importantly, with the LSPR and photothermal effect of plasmonic Au nanoparticles, the NiCoOx /Au anode provides additional current density of 7.01 mA cm-2 after illumination, and maintains no attenuation for more than 2000 s. Benefiting from the solution of agglomeration problem of plasmonic Au nanoparticles in the long-time OER process and the effective utilization of generated holes of plasmonic Au nanoparticles, this design can provide guidance for the application of plasmonic materials in the field of electrocatalysis.