Plasmon‐Dictated Photo‐Electrochemical Water Splitting for Solar‐to‐Chemical Energy Conversion: Current Status and Future Perspectives

Abstract

attention has been devoted to the conversion of solar light into chemical energy for satisfying increasing demands of energy consumption, such as photocatalysis, photovoltaics, and photoelectrocatalysis. [3,4] In particular, photo-electrochemical (PEC) water splitting with assistance of solar light for hydrogen production has been deemed as a rather promising route to ameliorate the increasing energy crisis since the pioneer work launched in 1972 by Honda and Fujishima, who judiciously harnessed TiO 2 powder electrode to achieve water splitting under UV light irradiation. [5][6][7] Thereafter, various semiconductors especially transition metal oxides have been extensively explored for PEC water splitting. Notwithstanding the advancements achieved in the past few decades, there still remain two issues that need to be circumvented with a view to fully utilizing the semiconducting materials for water splitting, including poor light-harvesting efficiency of wideband-gap semiconductors (e.g., TiO 2 , ZnO, SrTiO 3 , etc.), which only absorb UV light that accounts for merely 5% of the solar spectrum, and high recombination rate of photogenerated electron-hole charge carriers. To solve these problems, diverse strategies have been developed including (1) structure and/or morphology engineering for improving light trapping and shortening the travel distance of charge carriers to their surfaces, [8] (2) elemental doping to induce the formation of intraband gap state, [9,10] (3) sensitizing the semiconductor with organic dyes or narrow-band-gap quantum dots to improve the visible light absorption, [11][12][13][14][15][16][17][18] (4) construction of heterostructures or heterojunctions, [19,20] and (5) optimization of the crystal structure. [21] Nonetheless, it is worth noting that possible formation of undesirable defects at the interface and unfavorable stability of photosensitizers may occur in the above-mentioned strategies, which eventually retard the fabrication of highly efficient semiconductor-based photoelectrodes. Therefore, it is highly desirable to seek a more efficacious tactic to boost the photoresponse of wide band gap semiconductors.Decoration of semiconductors with metal nanostructures has been regarded as an alternative and powerful approach to improve the solar-to-hydrogen conversion efficiency of wideband-gap semiconductors by virtue of the intrinsically unique surface plasmon resonance (SPR) effect and electron capturing

Boosting Visible Light Harvesting in p‐Type Ternary Oxides for Solar‐to‐Hydrogen Conversion Using Inverse Opal Structure

“…[4,10] The nanostructuring strategies have already proven high effectiveness for improving the PEC performance because of the ability to capture more light and the enhanced charge transport arising from the unique optical and electrical properties. [15,[28][29][30][31][32] This IO metal oxide structure is often obtained using a two-step process: sol-infiltration into the interstices of the latex-based opal-template and removal of the template via calcination. [17,18] However, these structures are usually investigated only for simple binary oxides such as TiO 2 , WO 3 , and SnO 2, [19][20][21][22] whereas the complex growth mechanism and limited phase stability of multinary materials hinder preferential growth on certain crystallographic facets.…”

Plasmon‐Enhanced Photoluminescence and Photocatalysis Reactions in Metal‐Semiconductor Nanomaterials: UV‐Generated Hot Electron in Gold‐Zinc Oxide

“…As a result, the radiative recombination increases in ZnONPs, reflected by the PL enhancement. This phenomena is known by the PIRET effect (Plasmon Induced Resonance Energy Transfer) …”

“…This phenomena is known by the PIRET effect (Plasmon Induced Resonance Energy Transfer). [71] The enhancement of the UV PL by AuNPs under UV irradiation is illustrated in Figure 10(b).…”

Hierarchical Structure MnO2 Coated PDMS−Carbon Nanotube Sponge as Flexible Electrode for Electrocatalytic Water Splitting and High Performance Supercapacitor

“…In of the electrochemical reduction water splitting process, the HER process (2H + +2e − →H 2 ) is a relatively easy, which requires two electron transfer steps that can easily happen at low overpotential . Meanwhile, supercapacitors have an ability to bridge the energy/power gap between fuel cells/batteries and conventional capacitors . When supercapacitors are used in practical applications, three most important elements, high ionic and electronic conductivity, high surface area, and stability, are required to meet the charge/discharge rates, power and energy density, and long working life.…”