Spray-deposited Co-Pi Catalyzed BiVO4: a low-cost route towards highly efficient photoanodes

2012 ◽  
Vol 1446 ◽  
Author(s):  
Fatwa F. Abdi ◽  
Nienke Firet ◽  
Ali Dabirian ◽  
Roel van de Krol

ABSTRACTBismuth vanadate (BiVO4) thin films are deposited by a low-cost and scalable spray pyrolysis method. Its performance under AM1.5 illumination is mainly limited by slow water oxidation kinetics. We confirm that cobalt phosphate (Co-Pi) is an efficient water oxidation catalyst for BiVO4. The optimum thickness of BiVO4 is 300 nm, resulting in an AM1.5 photocurrent of 1.9 mA/cm2 at 1.23 V vs. RHE when catalyzed with Co-Pi. Once the water oxidation limitation is removed, the performance is limited by low charge separation efficiency. This causes more than 60% of the electron-hole pairs to recombine before reaching the respective interfaces. The slow electron transport is shown to be the main cause of this low efficiency, and future efforts should therefore be focused on addressing this key limitation.

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Hanxiang Chen ◽  
Jianjian Yi ◽  
Zhao Mo ◽  
Yanhua Song ◽  
Wenshu Yang ◽  
...  

Abstract Photocatalysis technology has potential application in the field of energy and environment. How to expand visible light utilization and promote the separation efficiency of the carriers are the key issues for the high active photocatalysts preparation and future practical applications. In this work, a ternary metal sulfide Nb0.9Ta0.1S2 was prepared and used as an electron collector in the photocatalytic application. As a result, the generated electrons are quickly transferred to the surface of the composite to participate in the reaction. It was demonstrated that the photocatalytic activity of 2D-C3N4 was enhanced after the modification of Nb0.9Ta0.1S2. The Nb0.9Ta0.1S2/2D-C3N4 composite material was synthesized by solvothermal method. The composition of 5% Nb0.9Ta0.1S2/2D-C3N4 showed the highest H2 evolution rate of 1961.6 μmolg−1h−1, which was 6.6 times that of 2D-C3N4. The 15% Nb0.9Ta0.1S2/2D-C3N4 exhibited the best activity in Rhodamine B degradation rate of 97% in 2 h, which is 50% higher than that of 2D-C3N4. Nb0.9Ta0.1S2/2D-C3N4 can be used as electron trap to promote the effective separation of electron–hole pairs. This work provides benchmarks in exploring low-cost and efficient cocatalyst.


Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 926 ◽  
Author(s):  
Yury Kutin ◽  
Nicholas Cox ◽  
Wolfgang Lubitz ◽  
Alexander Schnegg ◽  
Olaf Rüdiger

Here we report an in situ electron paramagnetic resonance (EPR) study of a low-cost, high-stability cobalt oxide electrodeposited material (Co-Pi) that oxidizes water at neutral pH and low over-potential, representing a promising system for future large-scale water splitting applications. Using CW X-band EPR we can follow the film formation from a Co(NO3)2 solution in phosphate buffer and quantify Co uptake into the catalytic film. As deposited, the film shows predominantly a Co(II) EPR signal, which converts into a Co(IV) signal as the electrode potential is increased. A purpose-built spectroelectrochemical cell allowed us to quantify the extent of Co(II) to Co(IV) conversion as a function of potential bias under operating conditions. Consistent with its role as an intermediate, Co(IV) is formed at potentials commensurate with electrocatalytic O2 evolution (+1.2 V, vs. SHE). The EPR resonance position of the Co(IV) species shifts to higher fields as the potential is increased above 1.2 V. Such a shift of the Co(IV) signal may be assigned to changes in the local Co structure, displaying a more distorted ligand field or more ligand radical character, suggesting it is this subset of sites that represents the catalytically ‘active’ component. The described spectroelectrochemical approach provides new information on catalyst function and reaction pathways of water oxidation.


2018 ◽  
Vol 6 (24) ◽  
pp. 11377-11389 ◽  
Author(s):  
S. Sultana ◽  
S. Mansingh ◽  
K. M. Parida

Self regenerating oxygen vacancy rich CeO2NS–FeOOH/Fe2O3 hybrids are optimized and show superior charge separation efficiency both in visible and UV-visible light.


2019 ◽  
Vol 7 (28) ◽  
pp. 16992-16998 ◽  
Author(s):  
André Esteves Nogueira ◽  
Mario Rodrigo Santos Soares ◽  
João Batista Souza Junior ◽  
Carlos Alberto Ospina Ramirez ◽  
Flavio Leandro Souza ◽  
...  

A colloidal deposition process combined with the thermal spreading ability of Sb over hematite surface is used to obtain a mesoporous photoanode for water oxidation.


Author(s):  
Yuqing Shao ◽  
Zhaolin Dou ◽  
Xiaoyu Liang ◽  
Xinxin Zhang ◽  
Min Ji ◽  
...  

The photocatalytic reduction of CO2 into valuable fuels and sustainable energy has a promising future, yet remains a challenge due to low charge separation efficiency and inadequate active sites. We...


2018 ◽  
Vol 6 (21) ◽  
pp. 9839-9845 ◽  
Author(s):  
Sha-Sha Yi ◽  
Jun-Min Yan ◽  
Qing Jiang

The carbon quantum dot (CQD) sensitized integrated Ti:Fe2O3@g-C3N4 core–shell nanoarrays demonstrate superior PEC water oxidation performance which can be ascribed to efficient charge separation efficiency derived from the well-confined heterojunction structure together with the high catalytic activity of the CQDs for H2O2 decomposition.


2019 ◽  
Vol 30 (10) ◽  
pp. 1908492 ◽  
Author(s):  
Sanghyun Bae ◽  
Dongseok Kim ◽  
Hyunwoo Kim ◽  
Minsu Gu ◽  
Jungki Ryu ◽  
...  

2016 ◽  
Vol 52 (58) ◽  
pp. 9013-9015 ◽  
Author(s):  
Zhibin Luo ◽  
Chengcheng Li ◽  
Dong Zhang ◽  
Tuo Wang ◽  
Jinlong Gong

A highly-oriented Fe2O3/ZnFe2O4 heterojunction photoanode with well-defined morphology is featured for improving charge separation efficiency.


2018 ◽  
Vol 6 (46) ◽  
pp. 23478-23485 ◽  
Author(s):  
Feng Li ◽  
Jing Li ◽  
Lili Gao ◽  
Yiping Hu ◽  
Xuefeng Long ◽  
...  

In this study, we constructed an efficient hole migration pathway by integrating ultrathin amorphous NiOOH onto the Fe2O3 coating on F doped α-Fe2O3 nanorods. The resulting photoanode presents higher charge separation efficiency than most reported hematite-based photoanode.


Author(s):  
Yating Wang ◽  
Chaosheng Peng ◽  
Tao Jiang ◽  
Jing Zhang ◽  
Zheng Jiang ◽  
...  

To improve solar light harvesting and charge separation efficiency, we develop a facile strategy for synthesizing defect-engineered three-dimensionally ordered macroporous (3DOM) WO3 photonic crystals via colloidal crystal template method and...


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