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• Multitude advances were found for V-rich Bi 2 S 3 nanowire than pristine Bi 2 S 3 photoelectrode. • V-rich Bi 2 S 3 nanowires achieve excellent photocurrent density for water splitting under visible light. • Deep insights on how the V-rich feature affects the PEC performance of Bi 2 S 3. Bi 2 S 3 is a n-type (negative type) semiconductor that has a narrow band gap and an ideal band edge position for hydrogen generation. However, high charge recombination rate, low photoelectrochemical (PEC) efficiency and poor stability are of major concerns of Bi 2 S 3 as a photoelectrode. Herein, we report an efficient Vanadium-rich Bi 2 S 3 nanowires (atomic ratio of V to Bi is 1/22) that have been prepared on fluorine-doped tin oxide (FTO) substrate by an in-situ solution-processed reaction with BiVO 4 film as precursor. The resulting V-rich photoelectrode demonstrates notably high charge separation efficiency and fast charge transport with respect to pristine Bi 2 S 3 nanowires. As a result, the photocurrent density of ca. 10 mA·cm−2 at -0.2 V vs Ag/AgCl is obtained under visible light illumination. In addition, V-rich Bi 2 S 3 generates IPCE (incident photocurrent-to-current conversion efficiency) of 50% at 460 nm and 45% at 760 nm, demonstrating a 2.0 and 2.8-fold increase, respectively, when compared with pristine Bi 2 S 3. This enhancement is probably due to increased light absorption, less charge recombination, and faster charge transfer. More importantly, in contrast to pristine Bi 2 S 3 sample that suffers detrimental photocorrosion in sulfide containing electrolyte, V-rich Bi 2 S 3 nanowires retain 84.6% of its initial photocurrent over the course of 1 h. These findings are expected to shed light on engineering high-performance and robust metal sulfide materials for photoelectrochemical application. [ABSTRACT FROM AUTHOR]

Constructing isotype g‐C3N4/g‐C3N4 heterojunction is an approach to improve the efficiency of g‐C3N4 towards solar‐assisted oxidation of water. Such functional configuration can effectively overcome the intrinsic drawback of rapid charge recombination of g‐C3N4. Here, a modified g‐C3N4, with homogeneous phosphorus doping, is prepared in this work through a phosphide‐involved gas phase reaction. The resulting P‐g‐C3N4 displays altered electronic structure, including upshifted band edge potential, narrowed band gap and improved electronic conductivity. These features allow P‐g‐C3N4 as an outstanding candidate to form isotype junction with pristine g‐C3N4. As expected, the accelerated charge separation and migration in target junction is validated by various measurements. The optimized isotype g‐C3N4/P‐g‐C3N4 heterojunction achieves a photocurrent as high as 0.3 mA cm−2 at 1.23 V vs RHE (AM 1.5G, 100 mW cm−2), representing 8‐fold's enhancement compared with pristine g‐C3N4. The present strategy for constructing g‐C3N4‐based isotype heterojunction networks is found effective for large‐scale manufacturing. Isotype photoanode: A phosphorus‐doped g‐C3N4 with suitable electronic structure was explored to construct metal‐free isotype photojunction in large‐scale manufacturing. The percolated networks exhibit largely increased photocurrent than its single component as a result of efficient charge transfer being qualitatively identified. [ABSTRACT FROM AUTHOR]

Abstract: The paper reported the solution process of pentacene thin films from organic solvent O-dichlorobenzene. The pentacene thin films obtained from different conditions were characterized by X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), and UV–vis spectroscopy. The result shows that the pentacene solution was successfully obtained at a minimum temperature of 40°C. The optimum temperature of forming pentacene thin films was 100°C. [Copyright &y& Elsevier]

With the rapid development of economy, the past decades have experienced more and more severe energy depletion and environmental pollution issues, hence it is urgent to develop more environmental-friendly energy devices, such as fuel cells, metal-air batteries, water electrolysis and so on. However, such devices have long been suffering from the sluggish reaction kinetics and high energy barriers, plus the conventional electrocatalysts used in these devices mostly are noble-metal-based materials, such as Pt/C, IrO 2 , and RuO 2. These noble-metal-based electrocatalysts possess significant disadvantages such as high price, limited reserves, and undesirable stability, and these factors together hinder their large-scale industrial application and the inhomogeneity of the catalyst structure at the atomic level also impose great challenges to disclose the underlying catalytic mechanism. Noble metal nanoclusters, as a promising type of electrocatalyst with definitive composition and structure, have been attracting increasingly research efforts. This review aims to summarize the recent achievements of molecular metal nanoclusters employed in electrocatalytic processes, with particular elaboration on oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), oxygen evolution reaction (OER), as well as to unravel the catalytic mechanism and establish the relationship between its structure and functionality. Specifically, the size effect, the metal core configuration, charge effect, size effect, ligand effect, and metal-ligand binding motifs of the metal clusters that would impact the electrocatalytic performance are comprehensively discussed. In the end, the outlook and perspective including challenges and opportunities are proposed. We anticipate this review would be beneficial for gaining a deeper understanding of engineering nanoclusters for electrocatalysis and to expand its application in electrocatalysis. • The advantages using molecular metal clusters for electrocatalysis are highlighted. • Recent advances in ORR, HER, and OER by metal clusters are summarized. • Grand challenges and great opportunities in this field are elaborated. • It can stimulate more research efforts to advance this rapidly booming regime. [ABSTRACT FROM AUTHOR]

Tubular hematite with high-concentration, uniform doping is regarded as a promising material for photoelectrochemical water oxidation. However, the high-temperature annealing commonly used for activating doped hematite inevitably causes deformation of the tubular structure and an increase in the trap states. In the present work, Sn-doped tubular hematite on fluorine-doped tin oxide (FTO) is successfully obtained at 750 °C from a Sn-coated FeOOH tube precursor. Sn/P codoping, which is rarely considered for hematite, is also achieved via a gas phase reaction in phosphide atmosphere. The tubular morphology allows the dopant to diffuse from both the inner and outer surfaces, thus decreasing the doping profile in the radial direction. The even distribution of Sn and P synergetically increases the carrier density of hematite by one order of magnitude, which shortens the width of the depletion layer to ca. 2.3 nm (compared with 19.3 nm for the pristine sample) and leads to prolonged carrier lifetime and efficient charge separation. In addition, this codoping protocol does not introduce additional surface trap states, as evidenced by the increased charge injection efficiency and surface kinetic analysis using intensity modulated photocurrent spectroscopy (IMPS). As a result, the morphology- and doping-engineered hematite exhibits photocurrents of 0.9 mA cm−2 at 1.23 V and 3.8 mA cm−2 at 2.0 V vs. RHE under AM 1.5 G illumination (100 mW cm−2) in 1.0 M NaOH, representing 4.5-fold and 4.8-fold enhancements, respectively, compared with the photocurrents of undoped hematite. The present method is shown to be effective for preparing multi-element-doped hematite nanotubes and may find broad application in the development of other nanotubular photoelectrodes with or without doping for efficient and robust water oxidation. [ABSTRACT FROM AUTHOR]

Developing high surface area nanostructured electrodes with fast charge separation is one of the main challenges for exploring cupric oxide (CuO)-based photocathodes in solar-driven hydrogen production applications. Herein, brand new 1D branched CuO nanowire arrays have been achieved on fluorine-doped tin oxide-coated glass (FTO) through a two-step wet chemical redox reaction. X-ray diffraction patterns, Raman spectra and X-ray photoelectron spectroscopy confirm the pure phase characteristic of the resulting branched CuO. In addition to the enlarged surface area of this advanced functional structure as compared with that of the 1D wire trunk, the charge injection and separation have been improved by rationally controlling the density of defects and size of branches. As a result, the optimized branched CuO exhibits photocurrent as high as 3.6 mA·cm−2 under AM 1.5G (100 mW·cm−2) illumination and 3.0 mA·cm−2 under visible light (λ ＞ 420 nm) at 0.2 V vs. RHE in 0.5 M Na2SO4, which are 2.8- and 3.0-fold greater than those of 1D wire samples, respectively. In addition, the solution-processed approach established herein seems quite favourable for large-scale and low-cost manufacturing. [ABSTRACT FROM AUTHOR]

To overcome tough conditions currently used for the preparation of nanostructured hematite films on a conducting substrate, a rational and easy method of chemical etching involving Fe3+ release and material growth in the presence of OH− has been developed. By carefully tuning the parameters influencing the morphologies of hematite, including the synthetic procedure, the concentration of etching solution, temperature, etching time and the morphology controlling surfactant, hematite films grown on iron foil with various morphologies (e.g. nanorod, nanowire, ultrathin nanoflake and cauliflower-like shape) have been achieved. In particular, it is found that F− is an effective surfactant to control the morphology as well as the crystallization process of hematite. Ultrathin nanoflakes having a minimized feature size exhibit the best photocurrent of 0.5 mA cm−2 (1.23 V vs. RHE, RHE is reversible hydrogen electrode) among the samples tested as a result of facilitated hole diffusion to the electrolyte and thus lowered carrier recombination. Compared with pristine hematite, a nearly tripled photocurrent is observed when H2O2 is added in the electrolyte as a hole scavenger, suggesting the presence of a charge injection barrier in the surface of samples. According to this, the strategy of Co2+ treatment is utilized and the improved photocurrent is seen, likely due to the improved water oxidation kinetics and surface state passivation. We believe that this convenient and economical method can be extended to the synthesis of other alkaline metal oxide nanomaterials as long as the redox potential of S2O82−/SO42− is higher than Mn+/M (M refers to metal). [ABSTRACT FROM AUTHOR]

• A facile strategy to fabricate NiCo 2 Se 4 /NiCoS 4 heterostructure is developed. • NiCo 2 Se 4 /NiCoS 4 exhibited superior OER performance to IrO 2. • NiCo 2 Se 4 /NiCoS 4 showed excellent performance in water splitting and Zn-air battery. • It paves a path for preparing low cost and efficient catalysts with multifunctionalities. Rational design and constructing multifunctional electrocatalysts featuring with low cost and high efficiency is critical for promoting the implement of sustainable energy devices such as water splitting and zinc air batteries. Herein, we report a facile means to prepare a selenide/sulfide hetero-structured NiCo 2 Se 4 /NiCoS 4 catalyst for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), overall water splitting (OWS), and Zn-air batteries (ZABs). The NiCo 2 Se 4 /NiCoS 4 heterostructure showed excellent OER and HER performance, evidenced by the small overpotential of 248 mV and 180 mV @ 10 mA cm−2 for OER and HER, and superior long-term stability to the benchmark IrO 2 and Pt/C catalyst for OER and HER, respectively. It also exhibited a potential of 1.660 V @ 10 mA cm−2 in the practical OWS test, close to the Pt/C + IrO 2 catalyst. Furthermore, when employed as air-cathode catalyst for ZABs, the NiCo 2 Se 4 /NiCoS 4 modified battery exhibited the narrow charge-discharge voltage gap of 0.98 V @ 50 mA cm−2 and a maximal specific capacity of 693.17 mA h g−1, outperforming the IrO 2 counterpart. Such excellent performance can be attributed to the advantageous structural merit of the NiCo 2 Se 4 nanoflowers, and especially the heterostructure interfaces created in NiCo 2 Se 4 /NiCoS 4 , which significantly boosted the catalytic synergistic effects. This study can offer a new avenue to design and prepare abundant-element-based cost effective, efficient and durable electrocatalysts with multifunctionalities that hold great promises to be applied in electrochemical devices. Image, graphical abstract [ABSTRACT FROM AUTHOR]