Nanostructured Ternary Metal Tungstate-Based Photocatalysts for Environmental Purification and Solar Water Splitting:A Review

Visible-light-responsive ternary metal tungstate(MWO_4) photocatalysts are being increasingly investigated for energy conversion and environmental purification applications owing to their striking features, including low cost,eco-friendliness, and high stability under acidic and oxidative conditions. However, rapid recombination of photoinduced electron–hole pairs and a narrow light response range to the solar spectrum lead to low photocatalytic activity of MWO_4-based materials, thus significantly hampering their wide usage in practice. To enable their widespread practical usage, significant efforts have been devoted, by developing new concepts and innovative strategies. In this review, we aim to provide an integrated overview of the fundamentals and recent progress of MWO_4-based photocatalysts. Furthermore, different strategies, including morphological control, surface modification, heteroatom doping, and heterojunction fabrication, which are employed to promote the photocatalyticactivities of MWO_4-based materials, are systematically summarized and discussed. Finally, existing challenges and a future perspective are also provided to shed light on the development of highly efficient MWO_4-based photocatalysts.

Selectivity switch via tuning surface static electric field in photocatalytic alcohol conversion

Photocatalysis has shown great potential in organic reactions,while controlling the selectivity is a long-standing goal and challenge due to the involvement of various radical intermediates.In this study,we have realized selectivity control in the photocatalytic conversion of alcohols via engineering the surface static electric field of the CdS semiconductor.By leveraging the Au–CdS interaction to adjust lattice strain,which influences the intensity of the surface static electric field,we altered the pathways of alcohol conversion.The increased intensity of the surface static electric field changed the activation pathways of the C–H/O–H bond,leading to the selective formation of targeted C/O-based radical intermediates and altering the selectivity from aldehydes to dimers.A wide range of alcohols,such as aromatic alcohol and thiophenol alcohol,were selectively converted into aldehyde or dimer.This work provides an effective strategy for selectively controlling reaction pathways by generating a surface electric field.

Thermal annealing synthesis of double-shell truncated octahedral Pt-Ni alloys for oxygen reduction reaction of polymer electrolyte membrane fuel cells

Shape-controlled Pt-Ni alloys usually offer an exceptional electrocatalytic activity toward the oxygen reduction reaction(ORR)of polymer electrolyte membrane fuel ceils(PEMFCs),whose tricks lie in welldesigned structures and surface morphologies.In this paper,a novel synthesis of truncated octahedral PtNi_(3.5) alloy catalysts that consist of homogeneous Pt-Ni alloy cores enclosed by NiO-Pt double shells through thermally annealing defective heterogeneous PtNi35 alloys is reported.By tracking the evolution of both compositions and morphologies,the outward segregation of both PtOv and NiO are first observed in Pt-Ni alloys.It is speculated that the diffusion of low-coordination atoms results in the formation of an energetically favorable truncated octahedron while the outward segregation of oxides leads to the formation of NiO-Pt double shells.It is very attractive that after gently removing the NiO outer shell,the dealloyed truncated octahedral core-shell structure demonstrates a greatly enhanced ORR activity.The asobtained truncated octahedral Pt_(2.1)Ni core-shell alloy presents a 3.4-folds mass-specific activity of that for unannealed sample,and its activity preserves 45.4%after 30000 potential cycles of accelerated degradation test(ADT).The peak power density of the dealloyed truncated octahedral Pt2jNi core-shell alloy catalyst based membrane electrolyte assembly(MEA)reaches 679.8 mW/cm^(2),increased by 138.4 mW/cm^(2) relative to that based on commercial Pt/C.

MnWO_(4)nanorods embedded into amorphous MoS_(x)microsheets in 2D/1D MoS_(x)/MnWO_(4)S-scheme heterojunction for visible-light photocatalytic water oxidation

In this work,a novel amorphous molybdenum disulfide/manganese tungstate(MoS_(x)/MnWO_(4))hybrid in S-scheme heterojunction was designed and synthesized for photocatalytic water splitting to oxygen gen-eration under visible light.In the hybrids,a strong chemical interlayer between amorphous MoS_(x)mi-crosheets and MnWO_(4)nanorods was created by partial substitution of Mo for W,which increases charge transportation efficiency by reducing charge transfer barrier,verified by the computational density functional theory(DFT)and photoelectrochemical tests.A 0.5 wt%MoS_(x)/MnWO_(4)system(2D/1D)displayed a remarkable enhancement in photocatalytic activity of O_(2)evolution,up to 267.8μmol g^(-1)under visi-ble light illumination(>420 nm).The formed S-scheme heterojunction structure efficiently promotes the utilization of solar light and separation efficiency of photo-generated charge carriers,leading to the improvement of photocatalytic water oxidation performance.