Synergistic impact of cocatalysts and hole scavenger for promoted photocatalytic H2 evolution in mesoporous TiO2–NiSx hybrid

Photocatalytic solar energy conversion to hydrogen is sustainable and attractive for addressing the global energy and environmental issue. Herein, a novel photocatalytic system (NiS/Ni3S4 cocatalysts modified mesoporous TiO2) with superior photocatalytic hydrogen evolution capability through the synergistic impact of NiS/Ni3S4 (NiSx) cocatalyst and efficient hole scavenger has been demonstrated. The photocatalytic hydrogen evolution of TiO2-NiSx hybrids with the different content of NiSx and upon different organic hole scavengers was both investigated. The hybrid of TiO2 decorated with 3%(mole ratio of Ni^2+) NiSx cocatalyst in methanol solution showed the optimal photocatalytic hydrogen evolution rate of 981.59 μmol h^-1 g^-1 which was about 20 times higher than that of bare mesoporous TiO2. Our results suggested that the boosted hydrogen production performance is attributed to both the improved photoinduced electrons migration between NiS and Ni3S4 in cocatalyst and the high hole captured efficiency by hole scavengers of methanol.

Effects of nanostructure on clean energy: big solutions gained from small features

The increasing energy consumption and environmental concerns have driven the development of costeffective, high-efficiency clean energy. Advanced functional nanomaterials and relevant nanotechnologies are playing a crucial role and showing promise in resolving some energy issues. In this view, we focus on recent advances of functional nanomaterials in clean energy applications, including solar energy conversion, water splitting, photodegradation, electrochemical energy conversion and storage, and thermoelectric conversion, which have attracted considerable interests in the regime of clean energy.

Recent advances in synthesis strategies and solar-to-hydrogen evolution of 1T phase MS_(2)(M=W,Mo)co-catalysts

Photocatalytic water splitting is a promising strategy to produce hydrogen as a sustainable and clean energy carrier,based on abundant solar energy and semiconductor photocatalysts,and it has received extensive research and discussion over the past several decades.It is challenging,however,to achieve an efficient solar-to-hydrogen evolution process with a single particulate photocatalyst due to the weak solar spectrum harvest and the rapid recombination of photogenerated electron-hole pairs during the photocatalysis reaction.Combining semiconductors to create different co-catalysts presents a viable solution to the above issues.Recently,semiconductor photocatalysts modified by different transition metal sulfidebased co-catalysts with designed functions,especially in light absorption enhancement and chargecarrier-separation efficiency promotion,have attracted much attention.As continued breakthroughs have been made in the preparation,modification,and solar-to-hydrogen evolution application of the 1T phase MS_(2)(M=W,Mo)co-catalyst-based photocatalysis system in recent years,we believe that a comprehensive review of this kind of co-catalyst would further promote its research and development to address the energy and environmental challenges that we are currently facing.Herein,recent studies and progress are summarized on the fabrication of 1T phase MS_(2)(M=W,Mo)-based co-catalyst materials,as well as their roles and functional mechanisms for photocatalytic H;evolution.Finally,concluding perspectives on the opportunities in and challenges for the further exploration of the 1T-MS_(2)(M=W,Mo)-based solar-tohydrogen evolution system are presented.

Achieving simultaneous Cu particles anchoring in meso-porous TiO_(2) nanofabrication for enhancing photo-catalytic CO_(2) reduction through rapid charge separation

A facile solvo-thermal approach was successfully employed to prepare titanium oxide (TiO_(2)) nano-aggregates with simultaneous copper particles anchoring. The as-synthesized composite could convert CO_(2) into CH_(4) and CO products under simulated solar irradiation. The impact of copper loading amounts on the photo-reduction capability was evaluated. It was found proper amount of Cu loading could enhance the activity of CO_(2) photo-reduction. As a result, the optimal composite (TiO_(2)^(-)Cu-5%) consisting of TiO_(2) supported with 5% (mole ratio) Cu exhibits 2.2 times higher CH_(4) yield and 3 times higher CO yield compared with pure TiO_(2). Conduction band calculated from the band gap and valence X-ray photoelectron spectroscopy (XPS) indicated TiO_(2) nano-aggregates have suitable band edge alignment with respect to the CO_(2)/CH_(4) and CO_(2)/CO redox potential. Furthermore, with involving of Cu particles, an efficient separation of photo-generated charges was achieved on the basis of photocurrent response and photoluminescence spectra results, which contributed to the improved photo-catalytic performance. The present work suggested that the Cu-decorated TiO_(2) could serve as an efficient photo-catalyst for solar-driven CO_(2) photo-reduction.

Facilely anchoring Cu_(2)O nanoparticles on mesoporous TiO_(2)nanorods for enhanced photocatalytic CO_(2)reduction through efficient charge transfer

Semiconductor-employed photocatalytic CO_(2) reduction has been regarded as a promising approach for environmental-friendly conversion of CO_(2) into solar fuels.Herein,TiO_(2)/Cu_(2)O composite nanorods have been successfully fabricated by a facile chemical reduction method and applied for photocatalytic CO_(2) reduction.The composition and structure characterization indicates that the Cu_(2)O nanoparticles are coupled with TiO_(2) nanorods with an intimate contact.Under light illumination,all the TiO_(2)/Cu_(2)O composite nanorods enhance the photocatalytic CO_(2)reduction.In particular,the TiO_(2)/Cu_(2)O-15%sample exhibits the highest CH_(4)yield(1.35μmol g^(-1)h^(-1)) within 4 h irradiation,and it is 3.07 and 15 times higher than that of pristine TiO_(2)nanorods and Cu_(2)O nanoparticles,respectively.The enhanced photoreduction capability of the TiO_(2)/Cu_(2)O-15%is attributed to the intimate construction of Cu_(2)O nanoparticles on TiO_(2) nanorods with formed p-n junction to accelerate the separation of photogenerated electron-hole pairs.This work provides a reference for rational design of a p-n heterojunction photocatalyst for CO_(2) photoreduction.