Electronic Properties of Transition and Alkaline Earth Metal Doped CuS: A DFT Study.

CuS is a unique semiconductor with potential in optoelectronics. Its unusual electronic structure, including a partially occupied valence band, and complex crystal structure with an S-S bond offer unique opportunities and potential applications. In this work, the use of doping to optimize the properties of CuS for various applications is investigated by density functional theory (DFT) calculations. Among the dopants studied, Ni, Zn, and Mg may be the most practical due to their lower formation energies. Doping with Fe, Ni, or Ca induces significant distortion, which may be beneficial for achieving materials with high surface areas and active states. Significantly, doping alters the conductor-like behavior of CuS, opening a band gap by increasing bond ionicity and reducing the S-S bond covalency. Thus, doping CuS can tune the plasmonic properties and transform it from a conductor to an intrinsic fluorescent semiconductor. Ni and Fe doping give the lowest band gaps (0.35 eV and 0.39 eV, respectively), while Mg doping gives the highest (0.86 eV). Doping with Mg, Ca, and Zn may enhance electron mobility and charge separation. Most dopants increase the anisotropy of electron-to-hole mass ratios, enabling device design that exploits directional-dependence for improved performance.

Designing 3d metal oxides: selecting optimal density functionals for strongly correlated materials.

Transition metal oxides (TMOs) have remarkable physicochemical properties, are non-toxic, and have low cost and high annual production, thus they are commonly studied for various technological applications. Density functional theory (DFT) can help to optimize TMO materials by providing insights into their electronic, optical and thermodynamic properties, and hence into their structure-performance relationships, over a wide range of solid-state structures and compositions. However, this is underpinned by the choice of the exchange-correlation (XC) functional, which is critical to accurately describe the highly localized and correlated 3d-electrons of the transition metals in TMOs. This tutorial review presents a benchmark study of density functionals (DFs), ranging from generalized gradient approximation (GGA) to range-separated hybrids (RSH), with the all-electron def2-TZVP basis set, comparing magneto-electro-optical properties of 3d TMOs against experimental observations. The performance of the DFs is assessed by analyzing the band structure, density of states, magnetic moment, structural static and dynamic parameters, optical properties, spin contamination and computational cost. The results disclose the strengths and weaknesses of the XC functionals, in terms of accuracy, and computational efficiency, suggesting the unprecedented PBE0-1/5 as the best candidate. The findings of this work contribute to necessary developments of XC functionals for periodic systems, and materials science modelling studies, particularly informing how to select the optimal XC functional to obtain the most trustworthy description of the ground-state electron structure of 3d TMOs.

Accelerating Electron-Transfer and Tuning Product Selectivity Through Surficial Vacancy Engineering on CZTS/CdS for Photoelectrochemical CO2 Reduction.

Copper-based chalcogenides have been considered as potential photocathode materials for photoelectrochemical (PEC) CO2 reduction due to their excellent photovoltaic performance and favorable conduction band alignment with the CO2 reduction potential. However, they suffer from low PEC efficiency due to the sluggish charge transfer kinetics and poor selectivity, resulting from random CO2 reduction reaction pathways. Herein, a facile heat treatment (HT) of a Cu2 ZnSnS4 (CZTS)/CdS photocathode is demonstrated to enable significant improvement in the photocurrent density (-0.75 mA cm-2 at -0.6 V vs RHE), tripling that of pristine CZTS, as a result of the enhanced charge transfer and promoted band alignment originating from the elemental inter-diffusion at the CZTS/CdS interface. In addition, rationally regulated CO2 reduction selectivity toward CO or alcohols can be obtained by tailoring the surficial sulfur vacancies by HT in different atmospheres (air and nitrogen). Sulfur vacancies replenished by O-doping is shown to favor CO adsorption and the CC coupling pathway, and thereby produce methanol and ethanol, whilst the CdS surface with more S vacancies promotes CO desorption capability with higher selectivity toward CO. The strategy in this work rationalizes the interface charge transfer optimization and surface vacancy engineering simultaneously, providing a new insight into PEC CO2 reduction photocathode design.

DFT study of various tungstates for photocatalytic water splitting.

Tungsten oxide (WO3) is a promising photocatalytic material, but it has some limitations on its optoelectronic properties. Compared with binary materials, ternary compounds provide a much greater variety of compositions and hence properties, which can be tuned to suit particular applications. In this work, the effect of introducing a second metal cation into tungsten oxide is studied by Density Functional Theory (DFT) calculations. The compounds investigated include AWO4 tungstates (A = Sn, Fe), M2WO6 tungstates (M = Bi, Sb), tungstite (WO3·H2O) and hydrotungstite (WO3·2H2O). The tungstates studied are found to have either a small band gap (SnWO4, FeWO4, WO3·H2O and WO3·2H2O), and thus potentially improved visible-light activity compared with WO3, or a more negative conduction band edge than WO3 (Bi2WO6, Sb2WO6), which means they may be able to achieve overall water splitting, in contrast to WO3. The band gap narrowing and the band edge changes are attributed to the introduction of new electronic states due to the second metal cation, as well as structural changes, particularly a larger spacing between layers of WO6 octahedra. All the materials studied have a relative high static dielectric constant (εr > 10), allowing for exciton dissociation, and a small enough electron effective mass (me* < 0.5m0) along at least one direction for carrier diffusion. The performance of all the compounds is likely to be limited by poor hole mobility, except for Sb2WO6 and the hydrated compounds which also have a relatively small hole effective mass (mh* < 0.5m0). Through this comparative study, the key trends in properties as a function of composition for a family of complex materials have been identified, allowing appropriate compositions to be selected and tuned for specific applications.

DFT Study of Methanol Adsorption on Defect-Free CeO2 Low-Index Surfaces.

Methanol decomposition is a promising method for hydrogen production. However, the performance of current catalysts for this process is not sufficient for commercial applications. In this work, methanol adsorption on the CeO2 low-index surfaces is studied by density functional theory (DFT). The results show that methanol always dissociates spontaneously on the (100) surface, whereas dissociation on the (110) surface is site-selective; dissociation does not occur at all on the (111) surface, where only weak physisorption is found. The results confirm that surfaces with higher energies are more catalytically active. Analysis of the surface geometries shows that the dominant factors for the dissociation of methanol are the degree of undercoordination and the charges of the surface ions. The adsorption energy of each methanol molecule decreases with increasing coverage and there is a transition threshold between dissociative and associative adsorption. The present work indicates that a strategy to design catalysts with high activity is to maximize exposure of surfaces on which the ions have a high degree of undercoordination and a strong tendency to donate/accept electrons. The results demonstrate the importance of appropriately selecting and controlling exposed facets and particle morphology for optimizing catalyst performance.

Hybrid Solid Polymer Electrolytes with Two-Dimensional Inorganic Nanofillers.

Solid polymer electrolytes are of rapidly increasing importance for the research and development of future safe batteries with high energy density. The diversified chemistry and structures of polymers allow the utilization of a wide range of soft structures for all-polymer solid-state electrolytes. With equal importance is the hybrid solid-state electrolytes consisting of both "soft" polymeric structure and "hard" inorganic nanofillers. The recent emergence of the re-discovery of many two-dimensional layered materials has stimulated the booming of advanced research in energy storage fields, such as batteries, supercapacitors, and fuel cells. Of special interest is the mass transport properties of these 2D nanostructures for water, gas, or ions. This review aims at the current progress and prospective development of hybrid polymer-inorganic solid electrolytes based on important 2D materials, including natural clay and synthetic lamellar structures. The ion conduction mechanism and the fabrication, property and device performance of these hybrid solid electrolytes will be discussed.

Adventures in boron chemistry - the prediction of novel ultra-flexible boron oxide frameworks.

Recent periodic density functional calculations have predicted the existence of ultra-flexible low-energy forms of boron oxides in which rigid boron-oxygen heterocycles are linked by flexible B-O-B bridges. The minima in the energy landscapes of these frameworks are remarkably broad, with widths in excess of those of many hybrid metal-organic frameworks. Enormous changes in cell volume, which can exceed a factor of two, are accompanied by negligible changes in energy. Here we explore the underlying reasons for this behaviour using molecular electronic-structure calculations, periodic density functional theory and template-based geometric simulations. The angular flexibility of the B-O-B bridge depends only upon the geometry of the local B2O5 unit, independent of the configuration of neighbouring bridges. Unique cooperativity between the bending and twisting motions of the bridges leads to considerable anisotropy in framework flexibility. Exceptional flexibility is conferred not only by the intrinsic bending flexibility of the bridges but by topological factors, crucially the relaxation of torsional constraints when B3O3 rings are present. We test these conclusions by showing how the flexibility of the frameworks can be tuned by decoration with isoelectronic rings. The new nanoporous boron oxides presented in this work are predicted to be potential novel guest-host materials because of their flat energy landscapes. Furthermore, such structures can be generated systematically from silicates by the substitution of B2O54- for SiO44-. A borate analogue of ß-cristobalite is shown to be isoenergetic with the known B2O3-I polymorph. We raise the possibility of new families of frameworks and zeolite analogues.

Optical properties of zirconia ceramics for esthetic dental restorations: A systematic review.

STATEMENT OF PROBLEM: Yttria-stabilized tetragonal zirconia polycrystal has been used as a dental biomaterial for several decades because the fracture toughness and bend strength are increased by a stress-induced transformation-toughening mechanism. However, its esthetics are compromised by its poor translucency and grayish-white appearance. PURPOSE: The purpose of the present systematic review was to assess information on the mechanical, chemical, and optical requirements of monolithic zirconia dental restorations. MATERIAL AND METHODS: The following databases (2010 to 2015) were electronically searched: ProQuest, EMBASE, SciFinder, MRS Online Proceedings Library, Medline, Compendex, and Journal of the American Ceramic Society. The search was limited to English-language publications, in vitro studies, experimental reports, and modeling studies. RESULTS: The data from 57 studies were considered in order to review the intrinsic and extrinsic characteristics of zirconia and their effects on the optical properties. CONCLUSIONS: The materials and microstructural issues relevant to the esthetics and long-term stability of zirconia have been considered in terms of monolithic restorations, while there also are restorations specifically for esthetic applications. Although zirconia-toughened lithium silicate offers the best esthetic outcomes, transformation-toughened zirconia offers the best mechanical properties and long-term stability; cubic stabilized zirconia offers a potential compromise. The properties of these materials can be altered to some extent through the appropriate application of intrinsic (such as, annealing) and extrinsic (such as, shade-matching) parameters.

Elucidating the impact of A-site cation change on photocatalytic H2 and O2 evolution activities of perovskite-type LnTaON2 (Ln = La and Pr).

Transition metal (oxy)nitrides with perovskite-type structures have been regarded as one of the promising classes of inorganic semiconductor materials that can be used in solar water splitting systems for the production of hydrogen as a renewable and storable energy carrier. The performance of transition metal (oxy)nitrides in solar water splitting is strongly influenced by the crystal structure-related dynamics of photogenerated charge carriers. Here, we have systematically assessed the influence of A-site cation exchange on the visible-light-induced photocatalytic H2 and O2 evolution activities, photoanodic response, and dynamics of photogenerated charge carriers of perovskite-type LnTaON2 (Ln = La and Pr). The structural refinement results reveal the orthorhombic Imma and Pnma structures for LaTaON2 and PrTaON2, respectively; the latter has a more distorted crystal structure from the ideal cubic perovskite due to the smaller size of Pr3+ cations. Compared with LaTaON2, PrTaON2 exhibits lower photocatalytic H2 and O2 gas evolution activities and photoanodic response owing to an excessive amount of intrinsic defects associated with anionic vacancies and reduced tantalum species stemming from a long high-temperature nitridation process under reductive NH3 atmosphere. Transient absorption signals evidence the faster decay of photogenerated electrons (holes) in Pt (CoOx)-loaded LaTaON2 than that in Pt (CoOx)-loaded PrTaON2, consistent with the photocatalytic and photoelectrochemical performance of the two photocatalysts. This study suggests that in addition to selecting a suitable A-site cation, it is prerequisite to synthesize LnTaON2 (Ln = La and Pr) crystals with a low defect density to improve their photo-conversion efficiency for solar water splitting.

Band-Gap Control of Zinc Sulfide: Towards an Efficient Visible-Light-Sensitive Photocatalyst.

The electronic properties of transition-metal-doped zinc sulfide (ZnS) have been investigated by using first-principles calculations. Transition-metal doping can allow electronic transitions at energies corresponding to visible-light wavelengths, thus potentially resulting in increased photocatalytic efficiency under sunlight. In particular, our calculations show that transition-metal atoms that produce little lattice strain, such as Co, Ni, Mn, and Fe, can be readily incorporated in ZnS. Due to their low formation energies and appropriate band energies, we predict that Ni- and Co-doped ZnS will be promising materials for photocatalytic hydrogen production.

Stabilizing High-Voltage Performance of Nickel-Rich Cathodes via Facile Solvothermally Synthesized Niobium-Doped Strontium Titanate.

Ni-rich layered ternary cathodes are promising candidates thanks to their low toxic Co-content and high energy density (∼800 Wh/kg). However, a critical challenge in developing Ni-rich cathodes is to improve cyclic stability, especially under high voltage (>4.3 V), which directly affects the performance and lifespan of the battery. In this study, niobium-doped strontium titanate (Nb-STO) is successfully synthesized via a facile solvothermal method and used as a surface modification layer onto the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. The results exhibited that the Nb-STO modification significantly improved the cycling stability of the cathode material even under high-voltage (4.5 V) operational conditions. In particular, the best sample in our work could provide a high discharge capacity of ∼190 mAh/g after 100 cycles under 1 C with capacity retention over 84% in the voltage range of 3.0-4.5 V, superior to the pristine NCM811 (∼61%) and pure STO modified STO-811-600 (∼76%) samples under the same conditions. The improved electrochemical performance and stability of NCM811 under high voltage should be attributed to not only preventing the dissolution of the transition metals, further reducing the electrolyte's degradation by the end of charge, but also alleviating the internal resistance growth from uncontrollable cathode-electrolyte interface (CEI) evolution. These findings suggest that the as-synthesized STO with an optimized Nb-doping ratio could be a promising candidate for stabilizing Ni-rich cathode materials to facilitate the widespread commercialization of Ni-rich cathodes in modern LIBs.

Airborne agricultural particulate matter induces inflammatory cytokine secretion by respiratory epithelial cells: mechanisms of regulation by eicosanoid lipid signal mediators.

The purpose of this study was to elucidate the mechanism of the airborne poultry dust (particulate matter, PM)-induced respiratory tract inflammation, a common symptom in agricultural respiratory diseases. The study was based on the hypothesis that poultry PM would induce the release of inflammatory cytokine interleukin-8 (IL-8) by respiratory epithelial cells under the upstream regulation by cytosolic phospholipase A2 (cPLA2) activation and subsequent formation of cyclooxygenase (COX)- and lipoxygenase (LOX)-catalyzed arachidonic acid (AA) metabolites (eicosanoids). Human lung epithelial cells (A549) in culture were treated with the poultry PM (0.1-1.0 mg) for different lengths of time, following which PLA2 activity, release of eicosanoids and secretion of IL-8 in cells were determined. Poultry PM (1.0 mg/ml) caused a significant activation of PLA2 in a time-dependent manner (15-60 min), which was significantly attenuated by the calcium-chelating agents, cPLA2-specific inhibitor (AACOCF3) and antioxidant (vitamin C) in A549 cells. Poultry PM also significantly induced the release of COX- and LOX-catalyzed eicosanoids (prostaglandins, thromboxane A2 and leukotrienes B4 and C4) and upstream activation of AA LOX in the cells. Poultry PM also significantly induced release of IL-8 by the cells in a dose- and time-dependent manner, which was significantly attenuated by the calcium chelating agents, antioxidants and COX- and LOX-specific inhibitors. The current study for the first time revealed that the poultry PM-induced IL-8 release from the respiratory epithelial cells was regulated upstream by reactive oxygen species, cPLA2-, COX- and LOX-derived eicosanoid lipid signal mediators.

Dual-modification of Ni-rich cathode materials through strontium titanate coating and thermal treatment.

Ni-rich layered structure ternary oxides, such as LiNi0.8Co0.1Mn0.1O2 (NCM811), are promising cathode materials for high-energy lithium-ion batteries (LIBs). However, a trade-off between high capacity and long cycle life still obstructs the commercialization of Ni-rich cathodes in modern LIBs. Herein, a facile dual modification approach for improving the electrochemical performance of NCM811 was enabled by a typical perovskite oxide: strontium titanate (SrTiO3). With a suitable thermal treatment, the modified cathode exhibited an outstanding electrochemical performance that could deliver a high discharge capacity of 188.5 mAh/g after 200 cycles under 1C with a capacity retention of 90%. The SrTiO3 (STO) protective layer can effectively suppress the side reaction between the NCM811 and the electrolyte. In the meantime, the pillar effect provided by interfacial Ti doping could effectively reduce the Li+/Ni2+ mixing ratio on the NCM811 surface and offer more efficient Li+ migration between the cathode and the coating layer after post-thermal treatment (≥600 °C). This dual modification strategy not only significantly improves the structural stability of Ni-rich layered structure but also enhances the electrochemical kinetics via increasing diffusion rate of Li+. The electrochemical measurement results further disclosed that the 3 wt% STO coated NCM811 with 600 °C annealing exhibits the best performance compared with other control samples, suggesting an appropriate temperature range for STO coated NCM811 cathode is critical for maintaining a stable structure for the whole system. This work may offer an effective option to enhance the electrochemical performance of Ni-rich cathodes for high-performance LIBs.

Enhancing the Electrochemical Properties of Nickel-Rich Cathode by Surface Coating with Defect-Rich Strontium Titanate.

Ni-rich layered ternary cathodes (i.e., LiNixCoyMzO2, M = Mn or Al, x + y + z = 1 and x ≥ 0.8) are promising candidates for the power supply of portable electronic devices and electric vehicles. However, the relatively high content of Ni4+ in the charged state shortens their lifespan due to inevitable capacity and voltage deteriorations during cycling. Therefore, the dilemma between high output energy and long cycle life needs to be addressed to facilitate more widespread commercialization of Ni-rich cathodes in modern lithium-ion batteries (LIBs). This work presents a facile surface modification approach with defect-rich strontium titanate (SrTiO3-x) coating on a typical Ni-rich cathode: LiNi0.8Co0.15Al0.05O2 (NCA). The defect-rich SrTiO3-x-modified NCA exhibits enhanced electrochemical performance compared to its pristine counterpart. In particular, the optimized sample delivers a high discharge capacity of ∼170 mA h/g after 200 cycles under 1C with capacity retention over 81.1%. The postmortem analysis provides new insight into the improved electrochemical properties which are ascribed to the SrTiO3-x coating layer. This layer appears to not only alleviate the internal resistance growth, from uncontrollable cathode-electrolyte interface evolution, but also acts as a lithium diffusion channel during prolonged cycling. Therefore, this work offers a feasible strategy to improve the electrochemical performance of layered cathodes with high nickel content for next-generation LIBs.

Improving density functional theory for crystal polymorph energetics.

We show that the quality of density functional theory (DFT) predictions for the relative stabilities of polymorphs of crystalline para-diiodobenzene (PDIB) is dramatically improved through a simple two-body correction using wavefunction-based electronic structure theory. PDIB has two stable polymorphs under ambient conditions, and like Hongo et al. [J. Phys. Chem. Lett., 1, 1789 (2010)] we find that DFT makes wildly variable predictions of the relative stabilities, depending on the approximate functional used. The two-body corrected scheme, using Grimme's spin-scaled variant of second-order Møller-Plesset perturbation theory and any of the tested density functionals, predicts the α-polymorph to be more stable, consistent with experiment, and produces a relative stability that agrees with the benchmark quantum Monte-Carlo results of Hongo et al. within statistical uncertainty.

Density Functional Theory Investigation of the Biocatalytic Mechanisms of pH-Driven Biomimetic Behavior in CeO2.

There is considerable interest in the pH-dependent, switchable, biocatalytic properties of cerium oxide (CeO2) nanoparticles in biomedicine, where these materials exhibit beneficial antioxidant activity against reactive oxygen species (ROS) at a basic physiological pH but cytotoxic prooxidant activity in an acidic cancer cell pH microenvironment. While the general characteristics of the role of oxygen vacancies are known, the mechanism of their action at the atomic scale under different pH conditions has yet to be elucidated. The present work applies density functional theory (DFT) calculations to interpret, at the atomic scale, the pH-induced behavior of the stable {111} surface of CeO2 containing oxygen vacancies. Analysis of the surface-adsorbed media species reveals the critical role of pH on the interaction between ROS (•O2- and H2O2) and the defective CeO2 {111} surface. Under basic conditions, the superoxide dismutase (SOD) and catalase (CAT) biomimetic reactions can be performed cyclically, scavenging and decomposing ROS to harmless products, making CeO2 an excellent antioxidant. However, under acidic conditions, the CAT biomimetic reaction is hindered owing to the limited reversibility of Ce3+ ↔ Ce4+ and formation ↔ annihilation of oxygen vacancies. A Fenton biomimetic reaction (H2O2 + Ce3+ → Ce4+ + OH- + •OH) is predicted to occur simultaneously with the SOD and CAT biomimetic reactions, resulting in the formation of hydroxyl radicals, making CeO2 a cytotoxic prooxidant.

Optical Tuning of Resistance Switching in Polycrystalline Gallium Phosphide Thin Films.

The nanoscale resistive switching characteristics of gallium phosphide (GaP) thin films directly grown on Si are investigated as a function of incident light. The formation of conductive channels along the grain boundaries is attributed to the presence of point defects and structural disorder, which provide the ideal environment to enable the filamentary switching process. Both first-principles calculations and UV-vis and photoluminescence spectroscopy strongly point to the possibility of mid-gap electronic states in the polycrystalline GaP film due to such defects. To study the photonic excitation, photoconductive atomic force microscopy (phAFM) measurement is conducted. We observe photocurrents even for incident photon energies lower than the band gap, consistent with the presence of mid-gap electronic states; the photocurrents increase in direct proportion to the incident photon energy with a concomitant decrease in the filament resistance. This demonstrates GaP directly integrated on Si can be a promising photonic resistive switching materials system.

Predicting crystal structures ab initio: group 14 nitrides and phosphides.

Crystal structures are predicted for a range of group 14 nitrides and phosphides with 1 : 1 stoichiometry, following our method of starting from the known structures for a range of binary compounds and looking for trends in the preferred local bonding environments in the optimised structures. We have previously applied this method to predict the structures of carbon nitride and phosphorus carbide. Here, we use a similar approach to predict the structures of silicon and germanium nitrides and phosphides with 1 : 1 stoichiometry. We find that the local bonding environments in the preferred structures for the nitrides are the same as those for the 3 : 4 stoichiometry. For the phosphides, we have found several possible structures with similar energies. Structures containing hypervalent phosphorus must be considered as these are often low in energy, particularly for GeP; these have not been included in previous work. The greater tendency to form hypervalent phosphorus in GeP than SiP can be rationalised by considering the bond enthalpies for the two compositions.

Dynamic single-site polysulfide immobilization in long-range disorder Cu-MOFs.

The structural transformation of MOFs in a polysulfide electrode process is poorly understood. We report the electrochemical amorphization of Cu3(BTC)2 MOFs in polysulfide electrolyte. We unveil the dynamic single-site polysulfide immobilization at the interconvertible Cu2+/Cu+ cation centres upon polysulfide adsorption and desorption, along with the reversible distortion of the Cu-O square planar unit.

Light-Induced Formation of MoOxSy Clusters on CdS Nanorods as Cocatalyst for Enhanced Hydrogen Evolution.

Metal and metal-oxide particles are commonly photodeposited on photocatalysts by reduction and oxidation reactions, respectively, consuming charges that are generated under illumination. This study reveals that amorphous MoOxSy clusters can be easily photodeposited at the tips of CdS nanorods (NRs) by in situ photodeposition for the first time. The as-prepared MoOxSy-decorated CdS samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma (ICP) to determine the composition and the possible formation pathways of the amorphous MoOxSy clusters. The MoOxSy-tipped CdS samples exhibited better hydrogen evolution performance than pure CdS under visible-light illumination. The enhanced activity is attributed to the formation of intimate interfacial contact between CdS and the amorphous MoOxSy clusters, which facilitates the charge separation and transfer. Through time-resolved photoluminescence (TRPL) measurements, it was clearly observed that all MoOxSy-decorated CdS samples with different loadings of MoOxSy showed a faster PL decay when compared to pure CdS, resulting from the effective trapping of photogenerated electrons by the MoOxSy clusters. Kelvin probe force microscopy (KPFM) was further used to study the surface potentials of pure CdS NRs and MoOxSy-decorated CdS NRs. A higher surface potential on MoOxSy-decorated CdS NRs was observed in the dark, indicating that the loading of MoOxSy resulted in a lower surface work function compared to pure CdS NRs. This contributed to the effective electron trapping and separation, which was also reflected by the increased photoelectrochemical response. Thus, this study demonstrates the design and facile synthesis of MoOxSy-tipped CdS NRs photocatalysts for efficient solar hydrogen production.