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Efficient utilization of a wide range of the solar spectrum in photoelectrochemical conversion is one of the primary requirements for photocatalyst materials. Here, we report an effective approach to combine solar-absorptive titanate-based oxide photocatalysts with titanium nitride (TiN) to demonstrate the enhanced photocurrent generation extending from the ultraviolet to the near-infrared region. Pseudobrookite Fe2TiO5 and Cr-doped TiO2 are, respectively, loaded on the TiN nanodisk arrays to demonstrate the photocurrent generation in opposite directions. By incorporating the TiN nanodisk arrays, the photocatalytic performance of Fe2TiO5 has increased by 26-fold in the UV region and ∼11-fold in the visible region due to the strong UV–visible light absorption, hot electron generation at the TiN nanodisk array, and their subsequent injection into the oxide. Similarly, the photocatalytic performance of Cr-TiO2 has increased by ∼18-fold in the UV region and ∼sixfold in the visible region by the hot hole transfer from TiN. This work demonstrates the effective utilization of titanium-based catalysts activated with both hot-electrons and holes from the TiN, yielding the visible-photocurrent generation and thus the improved photon management in solar photocatalysis. [ABSTRACT FROM AUTHOR]

\nImpact statementThe hydrogen evolution reaction (HER) is an important phenomenon in water splitting. Consequently, the development of an active, earth-abundant, and inexpensive HER catalyst is highly desired. MoS2 has drawn considerable interest as an HER catalyst because it is composed of non-precious metal and exhibits high catalytic activity in the nanosheet form. In this study, size-controlled MoS2 particles were synthesized by ball milling. The as-prepared samples exhibited significantly enhanced electrochemical and catalytic properties compared to those of pristine bulk MoS2. Furthermore, the HER activity improved further upon the introduction of graphene into the as-prepared ball-milled samples. In particular, the MoS2 sample ball-milled for 12 h mixed with graphene exhibited optimal performance, showing an overpotential (160 mV at 10 mA cm−2) that was ~335 mV lower than that of pristine bulk MoS2. The superior catalytic activity was ascribed to the exposed edge sites, sulfur vacancies, and 1T phase of MoS2, as well as the noteworthy fortifying effect of the electronically conductive flexible material, graphene. The results provide a promising strategy for its application as an efficient and stable HER catalyst.Li et al. reported MoS2-based electrocatalysts for the hydrogen evolution reaction. The superior catalytic activity was ascribed to exposed edge sites, sulfur vacancies, 1T phase, and the effect of graphene. [ABSTRACT FROM AUTHOR]

Mg substituted cobalt ferrite spinel powder samples with the general formula MgxCO1-xFe2O4(x = 0 to 0.25) were synthesized chemically through sol-gel method and annealed at 1100 °C for 2 h. They were initially screened for the structural and morphological properties by X-ray diffraction and field emission scanning electron microscopy, respectively. Vibrational properties of the samples were studied by Raman and infrared spectroscopies. X-ray diffraction confirmed the formation of single pure or near-pure phase with cubic spinel structure for all the samples with expected occupancy values. The field emission scanning electron microscopy revealed a decrease in the particle size with an increase in Mg concentration. Both structural and magnetic properties of the samples were characterized using Mössbauer spectroscopy while the magnetic properties were studied using vibrating sample magnetometry. The changes in magnetic moment of ions, their coupling with neighboring ions and cation exchange interactions were confirmed from the Mössbauer spectroscopy analysis. Saturation magnetization and coercivity values can be explained based on the Slater-Pauling curve. The magnetometry results showed a decrease in saturation magnetization of the samples with increase in Mg concentration [ABSTRACT FROM AUTHOR]

An efficient method of water purification and desalination using anodized aluminum oxide (AAO) loaded with titanium nitride nanoparticles (TiN NPs) is demonstrated. While the ceramic TiN NPs convert the incident sunlight into thermal energy and generate a hot forefront region at the water–vapor interface, the AAO serves as an efficient transporter of water to this evaporating region through its nanochannels. It has been shown that photothermal performance of TiN–AAO can be optimized by adjusting the pore diameter and nominal TiN thickness. Additionally, thermal insulation by a simple technique is effective in improving the water evaporation speed. Overall, the steam generation efficiency reaches 92% under solar irradiation of 100 mW cm−2. Low cost and concise design make the structure portable for solar steam generation. Titanium nitride (TiN) coated anodized aluminum oxide (AAO) converts the incident solar energy into thermal energy by photothermal conversion and efficient generation of steam. TiN–AAO can be used for solar distillation and desalination having 92% steam generation efficiency under solar irradiation of 100 mW cm−2. [ABSTRACT FROM AUTHOR]

Optical excitation of hot carriers in metals can be achieved even with low energy photons. When a metal comes in contact with a semiconductor, carrier injection can take place from the metal to the semiconductor even with photons possessing sub‐bandgap energies. While such internal photoemission has several decades of history, recent advances in plasmonics have brought the study of internal photoemission into a new era. The efficiency of hot carrier excitation can be improved drastically by rationally fabricating a metallic nanostructure to excite plasmon resonances. Moreover, the heating caused by the relaxation of plasmonic hot carriers is highly localized. These plasmon enhanced photoelectric and photothermal conversions have been studied intensively from fundamental and application‐oriented viewpoints, wherein gold and silver have been exclusively used. By contrast, this progress report covers nonmetallic materials that can be used for plasmon enhanced photoelectric and photothermal conversions. The main nonmetallic materials covered herein are transition metal nitrides, transition metal carbides, and metal oxides. Although research on nonmetallic materials for photoelectric and photothermal conversions is in the preliminary stage, some nonmetallic materials have been shown to outperform gold. This progress report aims to highlight the recent progress and discuss future research directions. Nonmetallic materials are an alternative to noble metals to excite hot carriers for photoelectric and photothermal conversions. This report outlines the recent progress in using transition metal nitrides, transition metal carbides, and metal oxides for photoelectric and photothermal applications. Although the field is preliminary, some of the nonmetallic materials possess superior photoelectric and photothermal properties to noble metals. [ABSTRACT FROM AUTHOR]