Porous 2D Catalyst Covers Improve Photoelectrochemical Water-Oxidation Performance.

Confined catalysis under the cover of 2D materials has emerged as a promising approach for achieving highly effective catalysts in various essential reactions. In this work, a porous cover structure is designed to boost the interfacial charge and mass transfer kinetics of 2D-covered catalysts. The improvement in catalytic performance is confirmed by the photoelectrochemical oxidation evolution reaction (OER) on a photoanode based on an n-Si substrate modified with a NiO thin-film model electrocatalyst covered with a porous graphene (pGr) monolayer.

A facile covalent strategy for ultrafast negative photoconductance hybrid graphene/porphyrin-based photodetector.

As a powerful complement to positive photoconductance (PPC), negative photoconductance (NPC) holds great potential for photodetector. However, the slow response of NPC relative to PPC devices limits their integration. Here, we propose a facile covalent strategy for an ultrafast NPC hybrid 2D photodetector.

Modification of interface and electronic transport in van der Waals heterojunctions by UV/O.

Two-dimensional (2D) van der Waals heterojunctions have many unique properties, and energy band modulation is central to applying these properties to electronic devices. Taking the 2D graphene/MoSheterojunction as a model system, we demonstrate that the band structure can be finely tuned by changing the graphene structure of the 2D heterojunction via ultraviolet/ozone (UV/O). With increasing UV/Oexposure time, graphene in the heterojunction has more defect structures.

Nanoarray Structures for Artificial Photosynthesis.

Conversion and storage of solar energy into fuels and chemicals by artificial photosynthesis has been considered as one of the promising methods to address the global energy crisis. However, it is still far from the practical applications on a large scale. Nanoarray structures that combine the advantages of nanosize and array alignment have demonstrated great potential to improve solar energy conversion efficiency, stability, and selectivity.

Interaction-Dependent Interfacial Charge-Transfer Behavior in Solar Water-Splitting Systems.

Dual-band-gap systems are promising for solar water splitting due to their excellent light-harvesting capability and high charge-separation efficiency. However, a fundamental understanding of interfacial charge-transfer behavior in the dual-band-gap configuration is still incomplete. Taking CdS/reduced graphene oxide (CdS/RGO) nanoheterojunctions as a model solar water splitting system, we attempt here to highlight the interaction-dependent interfacial charge-transfer behavior based on both experimental observations and theoretical calculations.

Vertically Aligned Porous Organic Semiconductor Nanorod Array Photoanodes for Efficient Charge Utilization.

Because of inefficient charge utilization caused by localized π-electron conjugation and large exciton binding energy, the photoelectrochemical water-splitting efficiency of organic polymers is seriously limited. Taking the graphitic carbon nitride (g-CN) polymer as an example, we report a novel photoanode based on a vertically aligned g-CN porous nanorod (PNR) array prepared in situ, using a thermal polycondensation approach, with anodic aluminum oxide as the template. The g-CN PNR array exhibits an excellent photocurrent density of 120.

Facile Integration between Si and Catalyst for High-Performance Photoanodes by a Multifunctional Bridging Layer.

Designing high-quality interfaces is crucial for high-performance photoelectrochemical (PEC) water-splitting devices. Here, we demonstrate a facile integration between polycrystalline np-Si and NiFe-layered double hydroxide (LDH) nanosheet array by a partially activated Ni (Ni/NiO) bridging layer for the excellent PEC water oxidation. In this model system, the thermally deposited Ni interlayer protects Si against corrosion and makes good contact with Si, and NiO has a high capacity of hole accumulation and strong bonding with the electrodeposited NiFe-LDH due to the similarity in material composition and structure, facilitating transfer of accumulated holes to the catalyst.

Sacrificial Interlayer for Promoting Charge Transport in Hematite Photoanode.

The semiconductor/electrolyte interface plays a crucial role in photoelectrochemical (PEC) water-splitting devices as it determines both thermodynamic and kinetic properties of the photoelectrode. Interfacial engineering is central for the device performance improvement. Taking the cheap and stable hematite (α-FeO) wormlike nanostructure photoanode as a model system, we design a facile sacrificial interlayer approach to suppress the crystal overgrowth and realize Ti doping into the crystal lattice of α-FeO in one annealing step as well as to avoid the consequent anodic shift of the photocurrent onset potential, ultimately achieving five times increase in its water oxidation photocurrent compared to the bare hematite by promoting the transport of charge carriers, including both separation of photogenerated charge carriers within the bulk semiconductor and transfer of holes across the semiconductor-electrolyte interface.

A photoelectrochemical investigation on the synergetic effect between CdS and reduced graphene oxide for solar-energy conversion.

CdS modified with reduced graphene oxide (RGO) has been widely demonstrated to be effective in the field of solar-energy conversion. However, the inherent mechanism of this superior property is still not thoroughly understood. Thus the photoelectrochemical method was employed to systemically investigate the synergetic effect between CdS and RGO.

Graphene-based materials for hydrogen generation from light-driven water splitting.

Hydrogen production from solar water splitting has been considered as an ultimate solution to the energy and environmental issues. Over the past few years, graphene has made great contribution to improving the light-driven hydrogen generation performance. This article provides a comprehensive overview of the recent research progress on graphene-based materials for hydrogen evolution from light-driven water splitting.