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31.
利用湿化学法制备先驱体-煅烧合成制备钒酸锆-ZrV2O7的新技术,采用粉末冶金方法,研究了ZrV2O7与金属Al两类不同材料的复合行为及其热膨胀特性。X射线衍射结果表明:利用上述技术合成的ZrV2O7纯度高,杂质含量极少。采用合成的ZrV2O7粉体与金属Al粉末混合,按不同成形-烧结工艺制备ZrV2O7与金属Al的复合材料试样,经扫描电子显微组织分析、微区电子探针能谱成分分析及X射线衍射分析发现,在一定烧结温度范围内,ZrV2O7与金属Al ( 无论是固态还是熔融态 ) 均表现出了良好的烧结性与浸渍性,但在烧结温度下在ZrV2O7与金属Al之间存在Al对Zr的置换反应,且随温度升高而加剧。用热膨胀仪分别对合成的ZrV2O7及其与金属Al烧结而成的复合材料进行热膨胀特性测试,结果表明:ZrV2O7在400~680K的温度区间具有很强的负膨胀特性;其与金属Al的复合材料虽然仍具有正的热膨胀特性,但其膨胀率较金属Al低得多。 相似文献
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《Ceramics International》2020,46(7):9040-9049
The transformation of solar energy into chemical energy stored as hydrogen fuel underlies the water splitting process into O2 and H2 in photo-electrochemical (PEC) cells. This a potentially promising technology to generate renewable and clean energy. To make this technology commercially viable, the engineering of appropriate low-cost and robust photo-electrode materials and substrates is needed. In this study, we introduce BiVO4-photoelectrodes grown on conductive bulk SnO2–Sb2O5 ceramics acting as porous substrate. For these photoelectrodes, the value of photocurrent density of 1.1 mA/cm2 was achieved in 0.1 M NaOH electrolyte at 1.23 V vs. RHE (reversible hydrogen electrode) under LED light (λ = 455 nm). This PEC performance of these BiVO4 photoelectrodes is reached in spite of using a simple and low-cost deposition technique, where the BiVO4-precursor is delivered to the bulk porous ceramic substrate as a nebulized aerosol in air-flow at room temperature. The high porosity of the ceramic substrate permits some permeation of the aerogel into the pores to a depth of several micrometers to provide a 3D-growth of the BiVO4-coating on conductive SnO2 grains. The film thickness of the BiVO4 on individual grains is approximately 100 nm. This construction of the photoelectrode leads to an effective interface with good absorption of solar radiation and good electron harvesting. The bulk ceramics assure favorable conditions for electron collection and charge transport, which results in a good PEC performance with this type of photoanode. 相似文献
34.
Sathish Kumar Ponnaiah Periakaruppan Prakash 《International Journal of Hydrogen Energy》2021,46(37):19323-19337
Herein we show a construction of high-performance supercapacitor electrode made of cerium vanadate uniformly glazed over polypyrrole (CeVO4/Ppy) nanostructures by a simple hydrothermal method, which was characterized by various analytical techniques. Electrochemical studies on CeVO4/Ppy/Ni foam with 1 M KOH show a maximum specific capacitance of 1236 F/g at a current density of 0.75 A/g. These salient features, together with smart interactions between the interconstituents, CeVO4 and Ppy, lead to high conductivity, specific capacitance, and cycling stability with retention of 92.6% capacitance in 10,000 cycles of GCD curves. Additionally, the asymmetric supercapacitor based on activated carbon (AC), AC//CeVO4/Ppy device delivers a high specific capacitance of 116 F/g and energy density of 52.2 Wh/Kg at power density of 675.9 W/kg along with high capacity retention of 77.80% after 10,000 cycles. This system could be scaled up to large-scale production of high power devices, which opens up lot of opportunities in modern electronic industrial applications. 相似文献
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36.
Åke Bergman 《Journal of the American Ceramic Society》1990,73(8):2564-2566
The relationship between phosphate and vanadate capacites and optical basicity, Λ, are used in order to settle the optical basicity of TiO2 . Phosphate and vanadate capacity data indicate that the optical basicity of TiO2 is 0.55. The validity of this value is supported by the good agreement with the value derived from Pauling electronegativity. 相似文献
37.
New Iron‐Cobalt Oxide Catalysts Promoting BiVO4 Films for Photoelectrochemical Water Splitting 下载免费PDF全文
Songcan Wang Tianwei He Jung‐Ho Yun Yuxiang Hu Mu Xiao Aijun Du Lianzhou Wang 《Advanced functional materials》2018,28(34)
Owing to the sluggish kinetics for water oxidation, severe surface charge recombination is a major energy loss that hinders efficient photoelectrochemical (PEC) water splitting. Herein, a simple process is developed for preparing a new type of low‐cost iron‐cobalt oxide (FeCoOx) as an efficient co‐catalyst to suppress the surface charge recombination on bismuth vanadate (BiVO4) photoanodes. The new FeCoOx/BiVO4 photoanode exhibits a high photocurrent density of 4.82 mA cm?2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination, which corresponds to >100% increase compared to that of the pristine BiVO4 photoanode. The photoanode also demonstrates a high charge separation efficiency of ≈90% with excellent stability of over 10 h, indicating the excellent catalytic performance of FeCoOx in the PEC process. Density functional theory calculations and experimental studies reveal that the incorporation of Fe into CoOx generates abundant oxygen vacancies and forms a p‐n heterojunction with BiVO4, which effectively promotes the hole transport/trapping from the BiVO4 photocatalyst and reduces the overpotential for oxygen evolution reaction (OER), resulting in remarkably increased photocurrent densities and durability. This work demonstrates a feasible process for depositing cheap FeCoOx as an excellent OER cocatalyst on photoanodes for PEC water splitting. 相似文献
38.
New BiVO4 Dual Photoanodes with Enriched Oxygen Vacancies for Efficient Solar‐Driven Water Splitting 下载免费PDF全文
Songcan Wang Peng Chen Yang Bai Jung‐Ho Yun Gang Liu Lianzhou Wang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(20)
Bismuth vanadate (BiVO4) is a promising photoanode material for photoelectrochemical (PEC) water splitting. However, owing to the short carrier diffusion length, the trade‐off between sufficient light absorption and efficient charge separation often leads to poor PEC performance. Herein, a new electrodeposition process is developed to prepare bismuth oxide precursor films, which can be converted to transparent BiVO4 films with well‐controlled oxygen vacancies via a mild thermal treatment process. The optimized BiVO4 film exhibits an excellent back illumination charge separation efficiency mainly due to the presence of enriched oxygen vacancies which act as shallow donors. By loading FeOOH/NiOOH as the cocatalysts, the BiVO4 dual photoanodes exhibit a remarkable and highly stable photocurrent density of 5.87 mA cm?2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination. An artificial leaf composed of the BiVO4/FeOOH/NiOOH dual photoanodes and a single sealed perovskite solar cell delivers a solar‐to‐hydrogen conversion efficiency as high as 6.5% for unbiased water splitting. 相似文献
39.
Efficient Solar Energy Harvesting and Storage through a Robust Photocatalyst Driving Reversible Redox Reactions 下载免费PDF全文
Yangen Zhou Shun Zhang Yu Ding Leyuan Zhang Changkun Zhang Xiaohong Zhang Yu Zhao Guihua Yu 《Advanced materials (Deerfield Beach, Fla.)》2018,30(31)
Simultaneous solar energy conversion and storage is receiving increasing interest for better utilization of the abundant yet intermittently available sunlight. Photoelectrodes driving nonspontaneous reversible redox reactions in solar‐powered redox cells (SPRCs), which can deliver energy via the corresponding reverse reactions, present a cost‐effective and promising approach for direct solar energy harvesting and storage. However, the lack of photoelectrodes having both high conversion efficiency and high durability becomes a bottleneck that hampers practical applications of SPRCs. Here, it is shown that a WO3‐decorated BiVO4 photoanode, without the need of extra electrocatalysts, can enable a single‐photocatalyst‐driven SPRC with a solar‐to‐output energy conversion efficiency as high as 1.25%. This SPRC presents stable performance over 20 solar energy storage/delivery cycles. The high efficiency and stability are attributed to the rapid redox reactions, the well‐matched energy level, and the efficient light harvesting and charge separation of the prepared BiVO4. This demonstrated device system represents a potential alternative toward the development of low‐cost, durable, and easy‐to‐implement solar energy technologies. 相似文献
40.
为了合成一种新型无机钒氧酸盐配合物[Zn2VO4(OH)]并对其进行结构分析,采用水热合成方法以V2O5、2,2'-联吡啶胺、ZnO和H2O为原料合成[Zn2VO4(OH)],并采用红外光谱、热重分析和x-射线衍射分析对该配合物的结构进行表征.结果表明,该配合物由简单的{VO4}3-单元构筑;配合物中含有Zn4O3OH立方体,且每个立方体均通过体外的OH官能团与其周围的6个立方体相连接并形成新型二维层;二维层之间再通过{VO4}3-桥连形成三维立体结构.{VO4}3-阴离子可以作为多齿配体,并可用来合成无机配合物. 相似文献