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Significant enhancement of stability for visible photocatalytic overall water splitting by assembling ultra-thin layer of NiO over Zn1-xCdxSX
摘要： Solar light driven water splitting into hydrogen and oxygen using visible light active photocatalyst has been considered as a clean, green, and renewable route to solar energy conversion and storage. Although Zn1-xCdxS catalyst shows comparatively higher activity for photocatalytic hydrogen generation under visible light irradiation, it suffers serious photocorrosion during the photocatalytic reaction. Deposition of protection layer over Zn1-xCdxS catalyst is believed to be an effective way to inhibit such photocorrosion. Nevertheless, seldom of protection layer exhibits satisfied catalytic properties for hydrogen evolution while presents good protection ability. In this work, a new Zn1-xCdxS photocatalyst has been developed for water splitting under visible light illumination by assembled an ultra-thin NiO layer over Zn0.8Cd0.2S via in-situ photodeposition method. By this strategy, NiO/Zn0.8Cd0.2S showed significant higher activity than Pt/Zn0.8Cd0.2S under same conditions without photocorrosion. The AQE of 0.66% for hydrogen evolution at 430 nm has been achieved and multi-cycle stability has been accomplished up to 12 hours without significant decay. Moreover, the strong electronic coupling between NiO layer and Zn1-xCdxS promoted efficient charge separation and migration.
关键词： Overall water splitting,sulfide semiconductor photocatalyst with thin NiO catalytic layer,enhanced charge separation and migration,significant enhanced stability,anti-photocorrosion
更新于2025-09-19 17:15:36
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Hierarchical CoFe-Layered double hydroxide and g-C3N4 heterostructures with enhanced bifunctional photo/ electrocatalytic activity towards overall water splitting
摘要： To achieve sustainable and clean energy for the hydrogen economy, developing efficient earth-abundant and non-noble transition metal photo/electrocatalysts toward overall water splitting is highly desirable. In this work, layered double hydroxide (LDH)@g-C3N4 composites with hierarchical flower-like micro/nanosheets and high surface area have been synthesized by a solvothermal method. HRTEM images exhibit that the surface of g-C3N4 nanosheets is highly orientation with the main exposure of (002) plane. Compared with the pristine CoFe-LDH, the hierarchical nanocomposite presents an excellent and stable electrocatalytic performance in 1.0 M KOH, with a small Tafel slope of 58 mV/dec and an overpotential of about 275 mV at a current density of 10 mA/cm2. Simultaneously, CoFe-LDH@g-C3N4 exhibits an exceptional performance for the HER in 1.0 M KOH electrolyte, with the overpotential of 417 mV at a current density of 10 mA/cm2 and a small Tafel slope of 77 mV/dec. Therefore, this work not only accomplishes improved catalytic activity of the CoFe-LDH by the introduction of g-C3N4 nanosheets, but also provides an insight into the correlation between the hierarchical flower-like morphologies and photo/electrochemical catalytic activity for overall water splitting.
关键词： bifunctional activity,photo/electrocatalysts,hierarchical CoFe-LDH@g-C3N4,solvothermal method,overall water splitting
更新于2025-09-19 17:15:36
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Charge Transfer Engineering via Multiple Heteroatom Doping in Dual Carbon-Coupled Cobalt Phosphides for Highly Efficient Overall Water Splitting
摘要： The exploration of non-noble-metal bifunctional electrocatalysts with high activity and stability for overall water splitting is crucial, but remains challenging for hydrogen fuel production. Herein, tuning of the charge transfer ability and catalytic performance of zeolitic imidazolate framework-derived porous carbon/reduced graphene oxide-coupled CoP composites (CoP@C@rGO) was achieved by incorporating multiple heteroatoms. The combined experimental investigation and density functional theory calculations revealed that the electronic interaction within the composites caused by B, N, and S tri-doped heteroatoms effectively induced interfacial charge transfer, which improved the active site accessibility and reduced the energy barriers of the evolution reaction; water splitting intermediates. From the synergetic effects of the components, the overall water splitting electrolyzer assembled using the newly prepared B,N,S-CoP@C@rGO catalyst required only 1.50 V to drive a current density of 10 mA cm–2, which is superior to the commercial Pt/C and IrO2/C couple (1.56 V).
关键词： hydrogen evolution reaction,oxygen evolution reaction,multiple doping,overall water splitting,charge transfer
更新于2025-09-12 10:27:22
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Laser Synthesis of Iridium Nanospheres for Overall Water Splitting
摘要： Engineering surface structure of catalysts is an efficient way towards high catalytic performance. Here, we report on the synthesis of regular iridium nanospheres (Ir NSs), with abundant atomic steps prepared by a laser ablation technique. Atomic steps, consisting of one-atom level covering the surface of such Ir NSs, were observed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The prepared Ir NSs exhibited remarkably enhanced activity both for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in acidic medium. As a bifunctional catalyst for overall water splitting, they achieved a cell voltage of 1.535 V @ 10 mA/cm2, which is much lower than that of Pt/C-Ir/C couple (1.630 V @ 10 mA/cm2).
关键词： overall water splitting,laser ablated nanoparticles,bifunctional catalyst,Ir nanoparticles
更新于2025-09-12 10:27:22
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A New Class of Zn <sub/>1</sub><i> <sub/>-x</sub></i> Fe <i> <sub/>x</sub></i> -Oxyselenide and Zn <sub/>1-</sub><i> <sub/>x</sub></i> Fe <i> <sub/>x</sub></i> -LDH Nanostructured Material with Remarkable Bifunctional Oxygen and Hydrogen Evolution Electrocatalytic Activities for Overall Water Splitting
摘要： The scalable and cost-effective H2 fuel production via electrolysis demands an efficient earth-abundant oxygen and hydrogen evolution reaction (OER, and HER, respectively) catalysts. In this work, for the first time, the synthesis of a sheet-like Zn1-xFex–oxyselenide and Zn1-xFex–LDH on Ni-foam is reported. The hydrothermally synthesized Zn1-xFex–LDH/Ni-foam is successfully converted into Zn1-xFex–oxyselenide/Ni-foam through an ethylene glycol-assisted solvothermal method. The anionic regulation of electrocatalysts modulates the electronic properties, and thereby augments the electrocatalytic activities. The as-prepared Zn1-xFex–LDH/Ni-foam shows very low OER and HER overpotentials of 263 mV at a current density of 20 mA cm?2 and 221 mV at 10 mA cm?2, respectively. Interestingly, this OER overpotential is decreased to 256 mV after selenization and the HER overpotential of Zn1-xFex–oxyselenide/Ni-foam is decreased from 238 to 202 mV at 10 mA cm?2 after a stability test. Thus, the Zn1-xFex–oxyselenide/Ni–foam shows superior bifunctional catalytic activities and excellent durability at a very high current density of 50 mA cm?2. More importantly, when the Zn1-xFex–oxyselenide/Ni-foam is used as the anode and cathode in an electrolyzer for overall water splitting, Zn1-xFex–oxyselenide/Ni-foam(+)∥Zn1-xFex–oxyselenide/Ni-foam(-) shows an appealing potential of 1.62 V at 10 mA cm?2. The anionic doping/substitution methodology is new and serves as an effective strategy to develop highly efficient bifunctional electrocatalysts.
关键词： Zn1-xFex–oxyselenide,Zn1-xFex–LDH,overall water splitting,HER,OER
更新于2025-09-10 09:29:36
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Carbon dots modified WO2-NaxWO3 composite as UV-Vis-NIR broad spectrum-driven photocatalyst for overall water splitting
摘要： The utilization of solar energy and valid photocatalyst is one of the most effective strategies to achieve water splitting into hydrogen (H2) and oxygen (O2). Although enormous effort has been devoted to photocatalysts, the sunlight still cannot be fully utilized by the developed photocatalysts. It is important but remains challenging to develop a broad spectrum-driven photocatalyst for overall water splitting. Here, we design a UV-Vis-NIR broad spectrum-driven carbon dots modified WO2-NaxWO3 (WO2-NaxWO3-CDs) composite as photocatalyst for overall water splitting without requirement of any sacrificial agents or cocatalysts. When the concentration of CDs in the sample is 0.008 gCDs/gcatalyst, the WO2-NaxWO3-CDs shows the highest photocatalytic activity with stoichiometric ratio of H2/O2 evolutions and their rates are 0.05/0.02, 2.58/1.24, 4.74/2.28 μmol/h under UV (λ< 420 nm), visible (420 nm≤λ≤760 nm) and near-infrared (λ>760 nm) light irradiation, respectively. It is also impressive that the photocatalyst shows excellent stability for about 6 cycles of repetitive experiments. The WO2-NaxWO3-CDs composites functioned as broad spectrum-driven photocatalyst for overall water splitting should attribute to the synergistic effect of WO2-NaxWO3 and CDs, in which the WO2-NaxWO3 provides the suitable bandgap, while the CDs can enhance light absorption and accelerate separation efficiencies of photo-generated charge carriers.
关键词： CDs,overall water splitting,broad spectrum,WO2-NaxWO3,photocatalyst
更新于2025-09-09 09:28:46