Exploiting effective photocatalytic materials especially co-catalysts is an effective solution to enhance solar hydrogen generation. In this work, we firstly introduce FeSe as highly efficient ...co-catalyst on the surface of CdS nanoparticles for photocatalytic H2 evolution under visible light irradiation. The optimized 2 wt% FeSe/CdS composite showed the highest photocatalytic H2 evolution activity of 204.4 μL/h with an apparent quantum efficiency of 6.71% at 420 nm, which is about 7 times higher than that of pure CdS nanoparticles. More importantly, 2 wt% FeSe/CdS composite also exhibits higher photocatalytic activity than that of 2 wt% Pt/CdS composite under the same condition. The higher photocatalytic H2 evolution property of FeSe/CdS composite is due to that the photo-generated electrons can be driven by the build-in field and transferred to the surface of FeSe causing electron-hole separation. This work may provide the potential applications of FeSe as a co-catalyst for photocatalytic H2 evolution.
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•FeSe/CdS composites have been successfully synthesized.•The photocatalytic H2 evolution activity of FeSe/CdS composite is about 7 times of pure CdS nanoparticles.•The photo-generated electrons can be driven by build-in field and transferred to the surface of FeSe.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The discovery and identification of novel active sites are paramount for deepening the understanding of the catalytic mechanism and driving the development of remarkable electrocatalysts. Here, we ...reveal that the genuine active sites for the hydrogen evolution reaction (HER) in LaRuSi are Si sites, not the usually assumed Ru sites. Ru in LaRuSi has a peculiar negative valence state, which leads to strong hydrogen binding to Ru sites. Surprisingly, the Si sites have a Gibbs free energy of hydrogen adsorption that is near zero (0.063 eV). The moderate adsorption of hydrogen on Si sites during the HER process is also validated by in situ Raman analysis. Based on it, LaRuSi exhibits an overpotential of 72 mV at 10 mA cm−2 in alkaline media, which is close to the benchmark of Pt/C. This work sheds light on the recognition of real active sites and the exploration of innovative silicide HER electrocatalysts.
Unlike other Ru‐containing compounds whose active sites are Ru sites, the Si sites in LaRuSi function as real active sites. The unusual negative valence Ru in this compound has excessively tight adsorption for hydrogen, according to both theoretical calculations and in situ Raman observations, but the Si sites have excellent hydrogen adsorption properties.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The separate modulation of the adsorption of *O and *OOH is challenging in oxygen evolution reaction (OER), which results in a large overpotential and slow kinetics. To balance the adsorption of the ...two active species, here, a way to regulate the local spin state and band structure simultaneously in Ni3S2 nanosheets is reported. The adequate doping of W heteroatoms causes the electron depletion from the Ni active site, which modulates the spin state of eg electrons, weakening the adsorption of *O. Additionally, the introduction of S vacancies contributes to the upshift of the d band center, which strengthens the adsorption of *OOH. In this manner, the adsorption of Ni3S2 for the active intermediates is optimized, resulting in a considerably improved overpotential of 246 mV at 100 mA cm−2 and a Tafel slope of 66 mV dec−1. This work provides insights into the exploration of OER catalysts through synergistic modulation of the spin state and the band structure.
Ni3S2 is co‐doped by W heteroatoms and S vacancies to regulate the local spin state and band structure simultaneously for advanced activity of oxygen evolution reaction.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Optimizing the hydrogen adsorption Gibbs free energy (ΔGH) of active sites is essential to improve the overpotential of the electrocatalytic hydrogen evolution reaction (HER). We doped graphene‐like ...Co0.85Se with sulfur and found that the active sites are reversed (from cationic Co sites to anionic S sites), which contributed to an enhancement in electrocatalytic HER performance. The optimal S‐doped Co0.85Se composite has an overpotential of 108 mV (at 10 mA cm−2) and a Tafel slope of 59 mV dec−1, which exceeds other reported Co0.85Se‐based electrocatalysts. The doped S sites have much higher activity than the Co sites, with a hydrogen adsorption Gibbs free energy (ΔGH) close to zero (0.067 eV), which reduces the reaction barrier for hydrogen production. This work provides inspiration for optimizing the intrinsic HER activity of other related transition metal chalcogenides.
Graphene‐like Co0.85Se was doped with sulfur, bringing about a reversal in active sites for the electrocatalytic hydrogen evolution reaction (HER) from cationic cobalt sites to anionic sulfur sites. A consequent change in the hydrogen adsorption Gibbs free energy (ΔGH) of the active sites improved the overpotential of the HER.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Significant efforts have been dedicated to boosting the electrocatalytic activity of Co9S8 for the oxygen evolution reaction (OER); however, with limited improvement in its intrinsic activity, which ...relies on careful band engineering. Fe possesses one less 3d electron and lower electronegativity than Co, suggesting a higher d‐band center when forming polyhedron with S anions. Here, to improve the intrinsic activity by elevating the d‐band center, the six‐coordinated octahedrons in Co9S8 are redesigned utilizing an Fe‐incorporated topochemical deintercalation method. Through substituting partial Co octahedrons by Fe octahedrons with higher d‐band, the overall d‐band center is regulated to achieve optimized adsorption and thus superior OER activity. With a reduction of 95 mV on the overpotential (at 10 mA cm−2), this work sheds lights on the design of OER catalysts through polyhedron engineering using topochemical deintercalation.
A series of Fe‐doped ultrasmall Co9S8 nanoparticles with a mean size of ≈4.5 nm are prepared through solid‐state synthesis and successive topochemical deintercalation to enhance oxygen evolution reaction performance.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Alloying noble metals with non‐noble metals is a promising method to fabricate catalysts, with the advantages of reduced noble metal usage and excellent activity. In this work, electron‐abundant ...Ir/Rh sites, as highly active centers for the hydrogen evolution reaction (HER), are realized by fabricating Ir1−xRhxSb alloys through the arc‐melting method. The electron transfer from Sb to Ir/Rh makes the latter negatively charged, leading to considerably optimized adsorption for active H species during HER. As a result, the Ir1−xRhxSb alloy exhibits outstanding activity for HER, with an optimized overpotential of 22 mV at 10 mA cm–2 and a Tafel slope of 47.6 mV dec–1. This work provides insights into highly active alloys and sheds light on the utilization of electron‐abundant metal atoms.
A ternary Ir1−xRhxSb intermetallic alloy is prepared through the arc‐melting method, with negatively charged metal sites for the hydrogen evolution reaction.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Laser ablation technology is utilized to produce a lychee-shaped RuO2@Ru/RuO2 structure to enhance the OER activity in both alkali and acidic solutions.
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Improving the OER activity of ...noble metal-based materials is of profound importance to minimize the usage of noble metals and lower the cost. Here, we report considerable improvement on the catalytic activity of RuO2 particles for OER in both alkali and acid environments. The RuO2 nanoparticles were treated with a method of pulse laser ablation. Numerous Ru and RuO2 clusters were generated at the surface of RuO2 nanoparticles after the laser ablation, forming a lychee-shaped morphology. The larger pulse energy RuO2 nanoparticles are treated with, the better the OER activity can be. DFT calculations shows that the surface tension induced by the lychee-shaped morphology benefits the OER performance. Our best sample gives an overpotential of 172 mV (at 10 mA cm−2) and a Tafel slope of 53.5 mV dec−1 in KOH, while an overpotential of 219 mV and a Tafel slope of 44.9 mV dec−1 in H2SO4, which are of top-class results. This work may inspire a new way to develop high-performance electrocatalysts for OER.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Li metal anode is considered as one of the most desirable candidates for next‐generation battery due to its lowest electrochemical potential and high theoretical capacity. However, undesirable ...dendrite growth severely exacerbates the interfacial stability, thus damaging battery performance and bringing safety concerns. Here, an efficient strategy is proposed to stabilize Li metal anode by digesting dendrites sprout using a 3D flexible superlithiophilic membrane consisting of poly(vinylidene fluoride) (PVDF) and ZnCl2 composite nanofibers (PZEM) as a protective layer. Both the experimental studies and theoretical calculations show the origin of superlithiophilicity ascribed to a strong interaction between ZnCl2 and PVDF to form the ZnF bonds. The multifield physics calculation implies effective removal of local dendrite hotspots by PZEM via a more homogeneous Li+ flux. The PZEM‐covered Li anode (PZEM@Li) exhibits superior Li deposition/stripping performance in a symmetric cell over 1100 cycles at a high current density of 5 mA cm−2. When paired with LiFePO4 (LFP), PZEM@Li|LFP full cell remains stable over 1000 cycles at 2 C with a degradation rate of 0.0083% per cycle. This work offers a new route for efficient protection of Li metal anode for practical applications.
Digesting dendrites for stable Li‐metal anode is successfully realized by using a flexible superlithiophilic poly(vinylidene fluoride) and ZnCl2 electrospinning membrane as an interfacial protective layer.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Geological disasters in hilly areas are related to Land-Use and Land-Cover Changes.•The number of geological disasters in the cultivated land area is the largest.•The point density of geological ...disasters and vegetation coverage is limited.•Geological disasters are more likely to occur in the period of heavy rainfall.•The closer geological disaster to river, the greater probability/scale of occurrence.
Sichuan hilly area is located in southwest China, which have many hilly area, is a densely populated, economically active, frequent geological disasters area. In this paper, Neijiang City in the region is taken as the test sample. This article, which analyzes Land-Use and Land-Cover Changes (LUCC), meteorological and hydrological data from 2015 to 2020, takes Neijiang City in this region as the research object. We explored the relationship between geological disasters such as collapse and landslides that often occur in the natural ecological environment with LUCC and meteorological and hydrological factors, using GIS spatial analysis and statistical analysis methods. The research results indicate that geological disasters mainly occur in farmland areas. The density of geological disaster points is highest within urban areas, making them the most prone to geological disasters. Geological disasters are more densely distributed in the area within 600 to 800 m from the river. There is a strong correlation between the average rainfall amount and the probability of geological disasters occurring. This study provides a scientific basis for the geological disaster risk assessment, prevention and control in this region. It has certain reference significance for the ecological environment governance, land resources planning and management in other similar regions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pulse laser has been widely used in both fundamental science and practical technologies. In this perspective, we highlight the employment of pulse laser ablation in air (LAA) in energy-related ...catalytic reactions. With LAA, samples are directly ablated in ambient air, which makes this technology facile to conduct. Materials can be modified by LAA in multiple aspects, such as morphology modulation, heterojunction fabrication, or defects engineering, which are desired features for energy-related catalytic reactions. We begin this perspective with a brief introduction of this technology, including the mechanism, the experimental setup, and the characteristic of laser-ablated materials. The recent works utilizing LAA are then summarized to prove the promising prospects of LAA in the energy field. Finally, several opportunities about the future usage of LAA are proposed and discussed.
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Laser; Energy storage; Energy materials
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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