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Abstract A comprehensive comparison study of the UV–visible photoresponse properties of non-aligned carbothermal ZnO nanowires (ZNWs) composited with reduced graphene oxide (RGO) and single-walled carbon nanotubes (SWCNTs) is presented. The RGO/ZNWs composites (GZWs) and SWCNTs/ZNWs composites (CZWs) have been successfully synthetized through UV-assisted photochemical reduction of GO in ZNWs suspension and ultrasonic stirring technology, respectively. The optimal contents of RGO and SWCNTs incorporated into ZNWs were determined for achieving maximum photoresponse, respectively. Experimentally, the optimal GZWs and CZWs exhibit significant enhancement in photoelectric properties than pure ZNWs. It is demonstrated that the GZWs-based photodetector has higher photoresponsivity (∼16 AW-1) than CZWs-based photodetector under low UV irradiation (<10 μWcm−2) and at 1.0 V bias, while the CZWs-based photodetector has higher on/off current ratio (8.41 × 104) and faster response time (1.99 s of rise-time and 0.39 s of decay-time) than GZWs-based one. The detail physics mechanism on the effects of RGO and SWCNTs on photoelectric characteristics of ZNWs is presented with the interface charge transfer due to the chemisorption and photo-desorption of oxygen. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Highly efficient direct energy conversion utilizing the betavoltaic effect is a promising alternative for developing of maintenance-free and long-life self-generating power cells. This work demonstrates a betavoltaic-powered electrochemical cell (BPEC) using free-standing TiO 2 nanotube arrays (TNTAs) incorporated with single-wall carbon nanotubes (SWCNTs) as the beta anode, a polyiodide (I − / I 3 − ) solution as the electrolyte, and a radioisotope 63Ni/Ni sheet as the cathode as well as the irradiation source. Freestanding TNTAs were fabricated using electrochemical anodization. Monte Carlo simulations were used to investigate the interaction of the incident beta particles with the TNTAs structure. Experimentally, the photoelectrochemical characteristics were used to optimize the structural design of the BPECs. The optimum BPEC exhibited an energy conversion efficiency of 8.74% with an open circuit voltage of 0.26 V and a short circuit current density of 0.87 μA/cm2. The enhanced betavoltaic effect is attributed to the highly efficient separation and transport of beta-generated carriers through the enhanced beta-electrochemical redox reactions in the 3-D TiO 2 /liquid heterojunction as well as the extensive SWCNTs conductive network. [Display omitted] • Monte Carlo simulation is used to investigate the interaction of beta particles with energy conversion structures. • TNTAs incorporated with SWCNTs were used as the beta-anode of BPECs. • Photoelectrochemical performance is used to evaluate and optimize the structure design of BPECs. • Beta-excited electrochemical reaction is enhanced by the 3-D TiO 2 /liquid heterojunction and SWCNTs conductive network. [ABSTRACT FROM AUTHOR]

Developing effective catalysts for the degradation of organic pollutants in the water as well as water-splitting for hydrogen production by using solar energy is a promising and green route for utilization and protection of water resources. In this study, a mesoporous TiO 2 /CeO 2 (m- TiO 2 /CeO 2) nanocomposite aerogel was prepared and defect-engineered using a facile sol-gel method assisted solvent exchange and hydrogenated thermal treatment. The hydrogenated black m -TiO 2 /CeO 2 nanocomposite aerogel exhibits the enhanced photocatalytic activity in the degradation of Rhodamine B (Rh B) and water splitting under visible-light irradiation. The degradation rate of Rh B reached ~96.4% in 60 min, and the hydrogen-evolution rate reached ~182 mmol h−1g−1, which are far higher than those of air-annealed m -TiO 2 sample. The photocatalytic enhancement mechanisms can be attributed to multiple strategies, such as the large specific surface area, the enhanced conductivity, the generation of self-doped defects in Z-scheme m -TiO 2 /TiO 2- x /CeO 2- x heterojunction, which are beneficial for providing more active sites, extending the absorption range of solar light, and suppressing the recombination of photo-excited carriers. [Display omitted] • The defect-engineered m -TiO 2 /CeO 2 aerogel was prepared using sol-gel method and hydrogenated thermal treatment. • The self-doped defects extend the visible light absorption of black m -TiO 2 /CeO 2 aerogel. • The migration of photoexcited charges in the m -TiO 2 /TiO 2- x /CeO 2- x heterojunction follow Z-scheme mechanism. [ABSTRACT FROM AUTHOR]