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Modification of nickel sulfide cocatalysts is considered to be a promising approach for efficient enhancement of the photocatalytic hydrogen production performance of g-C3N4. Providing more NiS cocatalyst to function as active sites of g-C3N4is still highly desirable. To realize this goal, in this work, a facile sulfur-mediated photodeposition approach was developed. Specifically, photogenerated electrons excited by visible light reduce the S molecules absorbed on g-C3N4surface to S2−, and subsequently NiS cocatalyst is formed in situ on the g-C3N4surface by a combination of Ni2+and S2−due to their small solubility product constant (Ksp= 3.2 × 10−19). This approach has several advantages. The NiS cocatalyst is clearly in situ deposited on the photogenerated electron transfer sites of g-C3N4, and thus provides more active sites for H2production. In addition, this method utilizes solar energy with mild reaction conditions at room temperature. Consequently, the synthesized NiS/g-C3N4photocatalyst achieves excellent hydrogen generation performance with the performance of the optimal sample (244 μmol h−1g−1) close to that of 1 wt% Pt/g-C3N4(316 μmol h−1g−1, a well-known excellent photocatalyst). More importantly, the present sulfur-mediated photodeposition route is versatile and facile and can be used to deposit various metal sulfides such as CoSx, CuSxand AgSxon the g-C3N4surface, and all the resulting metal sulfide-modified g-C3N4photocatalysts exhibit improved H2-production performance. Our study offers a novel insight for the synthesis of high-efficiency photocatalysts.

Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H 2 -evolution activity. In this study, S2−-adsorbed MoS x nanoparticle as a superior H 2 -evolutoin cocatalyst was successfully grafted on the TiO 2 surface to greatly boost its photocatalytic activity via one-step lactic acid-induced synthesis strategy. Herein, the lactic acid can induce the homogeneous production of amorphous MoS x (a-MoS x) nanoparticles from MoS 4 2− precursor, while the symbiotic S2- ions can be easily and availably self-adsorbed on the a-MoS x surface, resulting in the formation of S2--adsorbed a-MoS x nanoparticles with a small size of 0.5−3 nm. Photocatalytic results manifested that the S2−-adsorbed MoS x nanoparticles could dramatically facilitate the H 2 -generation rate of TiO 2 photocatalysts (3452 μmol h-1 g-1, AQE = 16.5 %). In situ irradiated XPS in conjunction with transient-state PL and photoelectrochemical tests reveal that the improved H 2 -generation activity can be ascribed to the synergistic effect of boosted interfacial charge transfer from TiO 2 to S2−-adsorbed MoS x and the superior H 2 -evolution reaction on self-adsorbed S2− ions. In addition, the S2−-adsorbed MoS x nanoparticles can also act as the general H 2 -generation cocatalyst to obviously promote the activity of other typical host photocatalysts such as g-C 3 N 4 and CdS. This work provides an innovative approach to develop high-efficiency MoS x -based cocatalyst with boosted interfacial charge transfer toward highly efficient photocatalytic materials. [ABSTRACT FROM AUTHOR]

Photocatalytic overall water splitting is a promising method for producing clean hydrogen energy, but faces challenges such as low light utilization efficiency and high charge carrier recombination rates. This study demonstrates that dielectric Mie resonance in TiO2hollow nanoshells can enhance electric field intensity and increase light absorption through resonant energy transfer, compared to crushed TiO2nanoparticles. The Mie resonance effect was confirmed through fluorescence spectra, photo-response current measurements, photocatalytic water splitting experiments, and Mie calculation. The incident electric-field amplitude was doubled in hollow nanoshells, allowing for increased light trapping. Additionally, the spatially separated Pt and RuO2cocatalysts on the inner and outer surfaces facilitated the separation of photoinduced electrons and holes. Pt@TiO2@RuO2hollow nanoshells exhibited superior photocatalytic water splitting performance, with a stable H2generation rate of 50.1 μmol·g−1·h−1and O2evolution rate of 25.1 μmol·g−1·h−1, outperforming other nanostructures such as TiO2, Pt@TiO2, and TiO2@RuO2hollow nanoshells. This study suggests that dielectric Mie resonance and spatially-separated cocatalysts offer a new approach to simultaneously enhance light absorption and charge carrier transfer in photocatalysis.

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A PbSe colloidal quantum dot (QD) is typically a solution-processed semiconductor for near-infrared (NIR) optoelectronic applications. However, the wide application of PbSe QDs has been restricted due to their instability, which requires tedious synthesis and complicated treatments before being applied in devices. Here, we demonstrate efficient NIR photodetectors based on the room-temperature, direct synthesis of semiconducting PbSe QD inks. The in-situ passivation and the avoidance of ligand exchange endow PbSe QD photodetectors with high efficiency and low cost. By further constructing the PbSe QDs/ZnO heterostructure, the photodetectors exhibit the NIR responsivity up to 970 mA/W and a detectivity of 1.86 × 1011Jones at 808 nm. The obtained performance is comparable to that of the state-of-the-art PbSe QD photodetectors using a complex ligand exchange strategy. Our work may pave a new way for fabricating efficient and low-cost colloidal QD photodetectors.