Recent Progress in Interface Engineering of Nanostructures for Photoelectrochemical Energy Harvesting Applications

With rapid and continuous consumption of nonrenewable energy, solar energy can be utilized to meet the energy requirement and mitigate environmental issues in the future. To attain a sustainable society with an energy mix predominately dependent on solar energy, photoelectrochemical (PEC) device, in which semiconductor nanostructure-based photocatalysts play important roles, is considered to be one of the most promising candidates to realize the sufficient utilization of solar energy in a low-cost, green, and environmentally friendly manner. Interface engineering of semiconductor nanostructures has been qualified in the efficient improvement of PEC performances including three basic steps, i.e., light absorption, charge transfer/separation, and surface catalytic reaction. In this review, recently developed interface engineering of semiconductor nanostructures for direct and high-efficiency conversion of sunlight into available forms (e.g., chemical fuels and electric power) are summarized in terms of their atomic constitution and morphology, electronic structure and promising potential for PEC applications. Extensive efforts toward the development of high-performance PEC applications (e.g., PEC water splitting, PEC photodetection, PEC catalysis, PEC degradation and PEC biosensors) are also presented and appraised. Last but not least, a brief summary and personal insights on the challenges and future directions in the community of next-generation PEC devices are also provided.

Synthesis of urchin-like Co3O4 spheres for application in oxygen evolution reaction

For oxygen evolution electrocatalysis of water splitting, unique urchin-shaped Co₃O₄ spheres were successfully grown on nickel foam by hydrothermal synthesis of Co(OH)F precursor and subsequent annealing method. The formation process was investigated by the evolution of phase structure and morphology with hydrothermal reaction time. And it can be explained by a 'disks-flowers-urchins' mechanism. Moreover, the Co₃O₄ urchins/NF exhibits considerable catalytic properties. It shows a low overpotential of 308 mV at a current density of 20 mA cm^-2 in alkaline solution. In the meantime, such material has a small Tafel slope of 82.1 mV dec^-1, large electrochemical active surface area and good long-term stability. The obvious promotion of oxygen evolution reaction performance can be attributed to the special morphology and the direct attachment to the substrate, which improve the exposed active sites, lower the internal resistance and accelerate the charge transport. Thus, the Co₃O₄ urchins/NF not only has a great potential promising behavior, but also provides the basis for subsequent performance improvement.

The S-hindered synthesis of PbSe/PbS nanosheets with enhanced electrochemical activities

A one-step synthesis of PbSe/PbS nanosheets for a Li ion battery.