Constructing efficient photoelectrochemical dual-electrode devices for solar hydrogen production is severely constrained by the lack of stable and high-performance p-type photocathodes. While doping wide-bandgap oxides can enable n-to-p type conversion and visible-light absorption, it frequently compromises charge transport due to dopant-induced recombination. Here, we overcome this trade-off by engineering a distributed p+-p- homojunction within a rhodium-doped SrTiO3 photocathode using pulsed laser deposition. By precisely tuning the Rh concentration gradient, we establish a steep "downhill" band alignment and a robust internal electric field that drives directional hole migration toward the substrate, effectively suppressing bulk recombination. Coupled with a BiVO4 photoanode, this transparent photocathode enables unbiased tandem water splitting with a stable solar-to-hydrogen efficiency of 0.45%. Our findings demonstrate that dopant-tailored homojunctions offer a generalizable strategy for mastering charge dynamics in complex oxide semiconductors, advancing efficient and durable oxide photocathodes for solar hydrogen production.

A type of solid oxide photoelectrochemical cell (SOPEC), where one of the electrodes is made from a photo-absorbing material, has been recently proposed as an innovative approach to enhance the performance of low-temperature energy conversion devices. For the further development of SOPECs, it is crucial to identify the interactions between the photo-response and surface defects in photoelectrodes. Variations in electron density caused by non-stoichiometric defects in photoelectrodes distort the energy band structure, thereby impacting their photo-response. However, the influence of the surface defects induced by electrochemical reactions on the photo-response of photoelectrodes remains poorly understood. Here, we have explored the photo-response of SrTiO3 (STO) as a photoelectrode in SOPECs during hydrogen-oxygen fuel cell operations. The formation of Sr vacancies on the STO surface induces a positive photovoltage under ultraviolet (UV) irradiation, resulting in a 90% increase in peak power density of the fuel cell. These findings underscore the significant potential of the SOPECs for practical applications.

A novel light-assisted fuel cell, termed a solid oxide photoelectrochemical cell (SOPEC), is proposed to enhance energy conversion efficiency at low temperatures.

Transition metal dichalcogenides (TMDs) have received considerable attention in recent years because of their intriguing chemical and physical properties. However, conventional synthesis methods, including chemical vapor deposition and wet-chemical synthesis, still face many challenges in mass production. Here, we develop a dynamic salt capsulation method to massively prepare TMDs (MoS2, 2 , WS2) 2 ) at atmospheric pressure in air with a high yield of over 95%. With the help of binary salts (KCl, KBr), TMDs can be easily obtained for a short reaction time of 1 h at a relatively low temperature (400 degrees C). degrees C). The as-synthesized MoS2 2 powders show flower-like nanospheres, which exhibit a desired catalytic performance in hydrogen evolution reactions and good electrochemical performance as anode materials in lithium-ion batteries. This work provides a simple method to synthesize high-quality and large quantities of TMDs with low cost and time consumption, which has a great potential to integrate into industrial production.

In the field of hydrogen production, MoS2 demonstrates good catalytic properties for the hydrogen evolution reaction (HER) which improve when doped with metal cations. However, while the role of sulfur atoms as active sites in the HER is largely reported, the role of metal atoms (i.e. molybdenum or the dopant cations) has yet to be studied in depth. To understand the role of the metal dopant, we study MoS2 thin films doped with Co and Mn ions. We identify the contribution of the electronic bands of the Mn and Co dopants to the integral valence band of the material using in situ resonant photoemission measurements. We demonstrate that Mn and Co dopants act differently: Mn doping favors the shift of the S-Mo hybridized band towards the Fermi level, while in the case of Co doping it is the less hybridized Co band that shifts closer to the Fermi level. Doping with Mn increases the effectiveness of S as the active site, thus improving the HER, while doping with Co introduces the metallic site of Co as the active site, which is less effective in improving HER properties. We therefore clarify the role of the dopant cation in the electronic structure determining the active site for hydrogen adsorption/desorption. Our results pave the way for the design of efficient materials for hydrogen production via the doping route, which can be extended to different catalytic reactions in the field of energy applications.

AbstractDesigning a high‐performance cathode is essential for the development of proton‐conducting solid oxide fuel cells (H‐SOFCs), and nanocomposite cathodes have proven to be an effective means of achieving this. However, the mechanism behind the nanocomposite cathodes' remarkable performance remains unknown. Doping the Co element into BaZrO3 can result in the development of BaCoO3 and BaZr0.7Co0.3O3 nanocomposites when the doping concentration exceeds 30%, according to the present study. The construction of the BaCoO3/BaZr0.7Co0.3O3 interface is essential for the enhancement of the cathode catalytic activity, as demonstrated by thin‐film studies using pulsed laser deposition to simulate the interface of the BCO and BZCO individual particles and first‐principles calculations to predict the oxygen reduction reaction steps. Eventually, the H‐SOFC with a BaZr0.4Co0.6O3 cathode produces a record‐breaking power density of 2253 mW cm−2 at 700°C.

Platinum doped oxides with extremely low utilization of noble metal and excellent catalytic activity have gained attention in high-temperature electrochemical cells. However, platinum ions tend to be reduced in reducing atmospheres, resulting in the catalyst deactivation. In this work, lanthanum is introduced into Pt-CeO2, which aims to deal with the above problem and provides an approach to promote Pt-CeO2 based catalysts for inter-mediate temperature solid oxide fuel cells. In specific, lanthanum doped Pt-CeO2 catalysts are prepared and infiltrated into the anode. The results show the highest peak power density with 10 mol% lanthanum doped Pt-CeO2 among all samples. In-situ ambient pressure X-ray photoemission spectroscopy investigation reveals that the reducibility of CeO2 can be tailored by lanthanum dopants, which leads to exceptional stability of active Pt2+ in reducing atmospheres. Our results foster the development of more stable and inexpensive Pt-CeO2 for inter-mediate temperature solid oxide fuel cells.

Finding suitable bifunctional catalysts for industrial hydrogen production is the key to fully building a hydrogen energy society. Here we report a modulation of the surface morphology of electrodeposited CoP to form hydrangea‐like Cobalt‐Iron bimetallic phosphide (B‐CoFeP@CoP) via ion‐exchange and NaBH4‐assisted methods. This catalyst exhibited excellent bifunctional catalytic capability at high current densities, achieving a current density of 500 mA cm‐2 at a small overpotential (387 mV for OER and 252 mV for HER). When assembled into an OWS electrolyzer, this catalyst showed a fairly low cell voltage (≈1.88 V) at 500 mA cm‐2 current density.，Furthermore, B‐CoFeP@CoP shows ceaseless durability over 120 h in both freshwater and seawater with almost no change in the cell voltage. A combined experimental and theoretical study identified that the unique hydrangea‐like structure provided a larger electrochemically active surface area and more effective active sites. Further analysis indicates that during the OER process, phosphides ensure that bimetallic active sites adsorb more OOH * intermediates and further DFT calculations showed that B‐Fe2P and B‐Co2P acted as active centers for dissociation of H2O and desorption of H2, respectively, to synergistically catalyze the HER process.

Cerium-based materials (CeO2−x) are of significant interest in the development of vacancy-modulated resistive switching (RS) memory devices. However, the influence of grain boundaries on the performance of memristors is very limited. To fill this gap, this study explores the influence of grain boundaries in cerium-based thin film resistive random-access memory (RRAM) devices. Sm0.2Ce0.8O2−x (SDC20) thin films were deposited on (100)-oriented Nb-doped SrTiO3 (NSTO) and (110)-oriented NSTO substrates using pulsed laser deposition (PLD). Devices constructed with a Pt/SDC20/NSTO structure exhibited reversible and stable bipolar resistive switching (RS) behavior. The differences in conduction mechanisms between single-crystal and polycrystalline devices were confirmed, with single-crystal devices displaying a larger resistance window and higher stability. Combining the results of XPS and I–V curve fitting, it was confirmed that defects near the grain boundaries in the SDC-based memristors capture electrons, thereby affecting the overall performance of the RRAM devices.

The built-in potential in the space charge layer dominates migration of charge carriers in a traditional photoelectrode model. In this work, through particle engineering and surface reconstruction, a Rh-doped rutile TiO2 (Rh-TiO2) photoelectrode is fabricated, in which the Rh concentration is decreased gradiently in TiO2 particle directed from conductive substrate to solution. Since the Rh dopants involve intragap states above the valence band of TiO2, it shapes a built-in potential that orients the migration of photoexcited holes toward substrate and repels the electrons to solution side, which change the Rh-TiO2 electrode from photoanode to photocathode. Comparison of intensity modulated photocurrent spectroscopy (IMPS) results using ultraviolet and visible light across a wide potential window unveils the different roles of dopants in charge dynamics. The operando chemical status of Rh is further verified by spectroelectrochemical characterization. The present strategy of directional doping not only is conducive to improving electron-hole separation but also provides a new approach to unleash the potential of a semiconductor as both photoanode and photocathode.

Yttrium-doped barium zirconate (BZY) thin films are widely used in the field of hydrogen energy because of their excellent proton conductivity and chemical stability. However, the existence of barium defects in BZY thin films fabricated by pulsed laser deposition (PLD) significantly hinders their intrinsic conductivity. In this regard, regulating the A-site nonstoichiometry for Ba-containing proton conductor oxides could control the proton transport properties. Herein, we used a target compensation strategy to compensate for the Ba loss in BZY thin films. We synthesized a series of nonstoichiometry graded Ba1+xZr0.8Y0.2O3-delta (Ba1+xZrY, 0.0 <= x <= 0.3) targets for growing Ba1+xZrY (0.0 <= x <= 0.3) thin films on MgO (100) substrates by PLD. The results show that the conductivity of the Ba1.3ZrY thin films is 1 order of magnitude larger than that of the Ba10ZrY thin films, exhibiting also lower activation energy. The structural characterization shows that the target compensation strategy can effectively fill the Ba vacancy and promote the proton transport of the Ba1+xZrY films, mainly attributed to the prolonged Zr-O bond length and increased Y dopant effective concentration.

Cocatalysts play a key role in enhancing activity of photoelectrodes while the study of their interaction remains a challenge. Here, we decoupled the relationship between oxygen evolution reaction (OER) performance and photoelectrochemical (PEC) water oxidation performance by modifying an identical BiVO4 with different cobalt-based OER catalysts including Co, CoO, Co3O4, and Co4N. The electrochemical OER activities of these cobalt specimens were quite similar. Their anodic photocurrent density followed an order of: Co4N>Co>Co3O4>CoO after loading on the BiVO4 electrode. The kinetics process and energy band diagram were analyzed, revealing that the interface between different cobalt specimens and BiVO4 electrode influenced the charge recombination and transfer. Accordingly, we propose a corresponding structural model, which shows that the cocatalysts consist of inner part for interface modulation and the outer layer for catalysis. The present work reveals the vital role of contact interface between cocatalysts and semiconductors, and more attention should be paid when selecting the cocatalysts.

Quantitative comparison of crystal symmetry and lattice volume effects on the proton conductivity of Y-doped Ba(Zr,Ce)O 3 epitaxial films to polycrystalline bulk materials reveals that lower crystal symmetry correlates with higher activation energy.

Promoting carbon circularity in the fashion industry to the next level driven by sustainability and resilience requires going beyond the current approaches. One consequence is a change in the current business models by integrating into the new energy and chemistry districts models to foster circularity and build resilience. They will play a crucial role in meeting the 2050 net-zero emissions target. The development of artificial leaf devices and solar fuels is discussed as one of the key technologies to enable this transition. The implications for the fashion industry are discussed.

Thehigh activity and selectivity of ceria in selective hydrogenationof alkynes have attracted much attention. However, the high operatingtemperature and the high H-2/alkyne ratios required hamperthe practical application of ceria catalysts, and the complex H-2-ceria interaction as well as the ambiguous role of oxygenvacancies (O-v) prevent the further reactivity optimizationof ceria-based catalysts. To elucidate the role of O-v sitesand hydride (Ce-H) species that can easily generate on ceriain the selective hydrogenation of propyne reaction, we constructedtwo model surfaces: CeO2(111) and CeO2-x (111)-H with H- ions preoccupiedin almost all of the O-v sites. From the catalytic performancemeasurements, both surfaces exhibit high selectivity for propene,while the CeO2-x (111)-Hsurface shows a propene production three times higher than CeO2(111). Using in situ ambient pressure X-ray photoelectronspectroscopy, we studied the formation and evolution of O-v, Ce-H, and carbon-containing species on the two surfacesduring the hydrogenation reaction and correlated with their catalyticperformance. Assisted by density functional theory calculations, wefound that surface-exposed O-v sites are required for theformation of Ce-H species and the dissociative adsorption ofpropyne. Meanwhile, Ce-H species possess high hydrogenationactivity and can help weaken the adsorption of CH3CCH2* to form gas-phase propene. The propene production and selectivityare optimal only in the coexistence of O-v sites and Ce-Hspecies with sufficient concentration. Our study has thus demonstratedthe crucial synergetic roles of O-v sites and hydride specieson ceria for the selective hydrogenation reaction.

Sustainability’s growth, year after year, continues to be staggering, becoming a reference point for those working on these issues [...]

Traditional lithium-ion batteries cannot meet the ever-increasing energy demands due to the unsatisfied graphite anode with sluggish electrochemical kinetics. Recently, the perovskite material family as anode attracts growing attention due to their advantages on specific capacity, rate capability, lifetime, and safety. Herein, a double perovskite La2 MnNiO6 synthesized by solid-state reaction method as a high-performance anode material for LIBs is reported. La2 MnNiO6 with an average operating potential of <0.8 V versus Li+ /Li exhibits a good rate capability. Besides, the Li|La2 MnNiO6 cells perform long cycle life without decay after 1000 cycles at 1C and a high cycling retention of 93% is observed after 3000 cycles at 6C. It reveals that this material maintains stable perovskite structure with cycling. Theoretical calculations further demonstrate the high electronic conductivity, low diffusion energy barrier, and structural stability of the lithiated La2 MnNiO6 . This study highlights the double perovskite type material as a promising anode for next-generation batteries.

Yttrium-doped barium zirconate (BZY) has been considered as a potential electrolyte candidate for intermediate-to-low temperature protonic ceramic fuel cell applications. However, the transport properties of BZY are often limited by the formation of highly resistive space charge zones at lattice discontinuities, such as lattice defects and surfaces. Unlike lattice defects, how to reduce the space charge effects at surfaces remains less explored. In this regard, surface defect engineering can be a meaningful way to regulate the proton transport of BZY by tailoring the space charge distribution close to the surface. Here, the Ar and/or O2 plasma was used to prepare BZY thin films with different levels of surface defects. The results of electrochemical impedance spectroscopy and detailed structural characterization suggest that the plasma treatment is effective in improving the proton conductivities and lowering the activation energy of BZY thin films through the generation of negatively charged barium vacancy defects and the enrichment of yttrium dopants on the surface.