Titanium Dioxide Microsphere-Derived Materials for Solar Fuel Hydrogen Generation

Abstract

Hydrogen fuel is an excellent energy carrier for the development of a low carbon emission economy that has the potential to solve the energy and environmental problems in the future. Photocatalytic H2 generation has received significant growth over the past few decades. Due to their unique properties, TiO2 microspheres have attracted much attention to be utilized in the photocatalytic H2 generation from water splitting. These microspheres-derived photocatalysts are known to offer the advantages of large surface area, tunable pore sizes, better allowing light absorption, efficient carrier separation, excellent electronic and optical properties, and high durability. Over the past few decades, significant research efforts have been allocated to the design of TiO2 microspheres with desired functionality for efficient H2 generation. This perspective will concentrate on recent advances in the synthesis of TiO2 microsphere-derived photocatalysts and their applications for efficient solar fuel H2 evolution from water splitting. Advanced strategies for the fabrication of TiO2 microsphere-based materials have been critically reviewed. The up-to-date developments of technologies applied to TiO2 microsphere-based materials for photocatalytic H2 evolution are compared and commented. Current challenges and future perspectives for solar fuel H2 generation will be also highlighted and discussed.

Recent Advances in the Synthesis of Layered, Double‐Hydroxide‐Based Materials and Their Applications in Hydrogen and Oxygen Evolution

“…One diagram for the process of photocatalytic hydrogen production on LDH‐derived materials is shown in Figure . If the irradiation of light with energy is greater than the bandgap of the LDH‐derived material, by separating the vacant conduction band (CB) and filling the valence band (VB), an electron is excited in the VB and jumps into the CB to result in the formation of an electron (e − )–hole (h + ) pair in the first stage . In the second stage, the photoexcited electron–hole pairs can either recombine or migrate to different surface reaction sites and drive a chemical reaction.…”

“…If the irradiation of light with energyi sg reater than the bandgap of the LDH-derived material,b ys eparating the vacant conduction band (CB) and filling the valence band (VB), an electron is excited in the VB and jumps into the CB to result in the formation of an electron (e À )-hole (h + )p air in the first stage. [91][92][93] In the second stage,t he photoexcited electron-hole pairs can either recombine or migrate to different surface reaction sites and drive ac hemical reaction. If the excited electrons and produced holes recombine quickly,t he energy is transferred to heat or re-emitted as photons,aprocess through which the absorbed energy is lost;a ss uch, the efficiency of the energyconversion process is decreased.…”

Effective Electron Transfer Pathway of the Ternary TiO2/RGO/Ag Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

“…TiO 2 photocatalyst is acknowledged as the most suitable material due to its excellent adjustable microstructure, chemical stability, non-toxicity, easy practicality and low cost [4][5][6][7][8]. However, there are still some defects mainly concentrated in the high recombination rate of photogenerated carriers and only absorbing UV light.…”

Selecting Support Layer for Electrodeposited Efficient Cobalt Oxide/Hydroxide Nanoflakes to Split Water

“…1−3 At the same time, sun, the free charge source of life, is the ultimate solution for the energy crisis which provides 120 000 TW radiations per year exceeding the whole world energy demand. 4 Considering solar hydrogen as the future energy carrier there are two main approaches in integrated solar water splitting devices: (i) capturing the light in proper semiconducting materials and conducting desired redox reaction (photoelectrochemical water splitting system) 5,6 and (ii) coupling and efficient solar cell to provide electric power and split water in a proper electrolyzer. 1,2,7 In both pathways, water is oxidized on the electrode surface involving transfer of four protons to the aqueous electrolyte and resulting in these two oxygen evolution reactions 8 according to the pH of the medium: 2 2 One of the main challenges in the solar fuel generation is the lack of a suitable electrocatalyst for reducing high oxygen evolution reaction (OER) overpotential and resulting water splitting at the minimum thermodynamic required energy (1.23 V at pH = 0) with an acceptable stability under harsh oxidizing conditions.…”