scholarly journals Ge-doped Hematite for an Unassisted Water Splitting System with Enhanced Efficiency

2020 ◽  
Author(s):  
Ki-Yong Yoon ◽  
Juhyung Park ◽  
Minsu Jung ◽  
Sang-Geun Ji ◽  
Hosik Lee ◽  
...  
Keyword(s):  
High Temperature ◽  
Water Splitting ◽  
Water Oxidation ◽  
Photocurrent Density ◽  
High Temperature Annealing ◽  
Sn Doping ◽  
Co Doping ◽  
Oxidation Performance ◽  
Splitting System ◽  
Ge Doping

Abstract To boost the photoelectrochemical water oxidation performance of a hematite photoanode, high temperature annealing has been widely applied to enhance crystallinity and remove the physical interface between the hematite and the fluorine doped thin oxide (FTO) substrate. However, the high temperature also results in unintentional Sn-doping due to thermal diffusion from the bottom FTO substrate. Therefore, when using additional dopants and the subsequent high temperature annealing process to enhance performance, the procedure should more precisely be considered co-doping of the hematite photoanode. However, at present, the interaction between the unintentional Sn and intentional dopant is poorly understood. Here, using germanium (Ge), which has been proven a promising dopant in previously reported simulations, we investigated how Sn diffusion affects overall PEC performance in Sn:Ge co-doped systems. After revealing the negative interaction of Sn and Ge dopants, we developed a facile Ge-doping method which suppresses Sn diffusion from the FTO substrate, significantly improving hematite performance. The Sn:Ge-hematite photoanode showed a photocurrent density of 4.6 mA cm− 2 at 1.23 VRHE with an excellent low turn-on voltage. After combining with a perovskite solar cell, our tandem system achieved outstanding 4.8% solar-to-hydrogen conversion efficiency (3.9 mA cm− 2 in an unassisted water splitting system). Our work provides important insights on a promising diagnostic tool for future co-doping system design.

scholarly journals NiFeOx decorated Ge-hematite/perovskite for an efficient water splitting system

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ki-Yong Yoon ◽  
Juhyung Park ◽  
Minsu Jung ◽  
Sang-Geun Ji ◽  
Hosik Lee ◽  
...  
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Photocurrent Density ◽  
Photoelectrochemical Performance ◽  
Co Doping ◽  
Solar Water Splitting ◽  
Oxidation Performance ◽  
Oxide Substrate ◽  
Splitting System ◽  
Co Doped

AbstractTo boost the photoelectrochemical water oxidation performance of hematite photoanodes, high temperature annealing has been widely applied to enhance crystallinity, to improve the interface between the hematite-substrate interface, and to introduce tin-dopants from the substrate. However, when using additional dopants, the interaction between the unintentional tin and intentional dopant is poorly understood. Here, using germanium, we investigate how tin diffusion affects overall photoelectrochemical performance in germanium:tin co-doped systems. After revealing that germanium is a better dopant than tin, we develop a facile germanium-doping method which suppresses tin diffusion from the fluorine doped tin oxide substrate, significantly improving hematite performance. The NiFeOx@Ge-PH photoanode shows a photocurrent density of 4.6 mA cm−2 at 1.23 VRHE with a low turn-on voltage. After combining with a perovskite solar cell, our tandem system achieves 4.8% solar-to-hydrogen conversion efficiency (3.9 mA cm−2 in NiFeOx@Ge-PH/perovskite solar water splitting system). Our work provides important insights on a promising diagnostic tool for future co-doping system design.

scholarly journals Synergies of co-doping in ultra-thin hematite photoanodes for solar water oxidation: In and Ti as representative case

RSC Advances ◽  
2020 ◽  
Vol 10 (55) ◽  
pp. 33307-33316
Author(s):  
Aadesh P. Singh ◽  
Camilla Tossi ◽  
Ilkka Tittonen ◽  
Anders Hellman ◽  
Björn Wickman
Keyword(s):  
Thin Film ◽  
Hydrogen Production ◽  
Solar Energy ◽  
Water Splitting ◽  
Water Oxidation ◽  
Representative Case ◽  
Solar Water ◽  
Co Doping ◽  
Pec Cells ◽  
Solar Water Oxidation

Solar energy induced water splitting in photoelectrochemical (PEC) cells is one of the most sustainable ways of hydrogen production. In this work, hematite (α-Fe2O3) thin film were modified by In3+ and Ti4+ co-doping for enhanced PEC performance.

scholarly journals An aqueous preoxidation method for monolithic perovskite electrocatalysts with enhanced water oxidation performance

2016 ◽  
Vol 2 (10) ◽  
pp. e1600495 ◽  
Author(s):  
Bo-Quan Li ◽  
Cheng Tang ◽  
Hao-Fan Wang ◽  
Xiao-Lin Zhu ◽  
Qiang Zhang
Keyword(s):  
Water Oxidation ◽  
Fenton Reaction ◽  
Nickel Foam ◽  
Three Dimensional ◽  
Active Phase ◽  
Perovskite Oxides ◽  
High Temperature Annealing ◽  
Current Collectors ◽  
Oxidation Performance

Perovskite oxides with poor conductivity call for three-dimensional (3D) conductive scaffolds to demonstrate their superb reactivities for oxygen evolution reaction (OER). However, perovskite formation usually requires high-temperature annealing at 600° to 900°C in air, under which most of the used conductive frameworks (for example, carbon and metal current collectors) are reductive and cannot survive. We propose a preoxidization coupled electrodeposition strategy in which Co2+ is preoxidized to Co3+ through cobalt Fenton reaction in aqueous solution, whereas the reductive nickel framework is well maintained during the sequential annealing under nonoxidative atmosphere. The in situ–generated Co3+ is inherited into oxidized perovskites deposited on 3D nickel foam, rendering the monolithic perovskite electrocatalysts with extraordinary OER performance with an ultralow overpotential of 350 mV required for 10 mA cm−2, a very small Tafel slope of 59 mV dec−1, and superb stability in 0.10 M KOH. Therefore, we inaugurate a unique strategy for in situ hybridization of oxidative active phase with reductive framework, affording superb reactivity of perovskite electrocatalyst for efficient water oxidation.

A graphene oxide–molecular Cu porphyrin-integrated BiVO4 photoanode for improved photoelectrochemical water oxidation performance

2020 ◽  
Vol 8 (7) ◽  
pp. 4062-4072 ◽  
Author(s):  
Chunjiang Xu ◽  
Wanjun Sun ◽  
Yinjuan Dong ◽  
Congzhao Dong ◽  
Qiyu Hu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Water Splitting ◽  
Water Oxidation ◽  
Bismuth Vanadate ◽  
Photoelectrochemical Water Splitting ◽  
Oxidation Performance ◽  
Photoelectrochemical Water Oxidation

Monoclinic bismuth vanadate (BiVO4), as a rising star in light-catching materials, has been researched in many fields, such as photoelectrochemical water splitting.

Large area high-performance bismuth vanadate photoanode for efficient solar water splitting

2020 ◽  
Vol 8 (7) ◽  
pp. 3845-3850 ◽  
Author(s):  
Meirong Huang ◽  
Wenhai Lei ◽  
Min Wang ◽  
Shuji Zhao ◽  
Changli Li ◽  
...  
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
High Performance ◽  
Large Scale ◽  
Photocurrent Density ◽  
Large Area ◽  
Solar Water ◽  
Solar Water Splitting ◽  
Harsh Conditions ◽  
Density Of Water

Large-scale BiVO4 photoanodes were prepared for solar water splitting. A photocurrent density of water oxidation of ∼2.23 mA cm−2 at 1.23 VRHE and ∼0.83% conversion efficiency at 0.65 VRHE were achieved, with <4% decay after 5 h of operation under harsh conditions.

scholarly journals Recent Developments in the Use of Heterogeneous Semiconductor Photocatalyst Based Materials for a Visible-Light-Induced Water-Splitting System—A Brief Review

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 160
Author(s):  
Prabhakarn Arunachalam ◽  
Keiji Nagai ◽  
Mabrook S. Amer ◽  
Mohamed A. Ghanem ◽  
Rajabathar Jothi Ramalingam ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Water Oxidation ◽  
Electrode Materials ◽  
Oxide Electrodes ◽  
Recent Developments ◽  
Visible Light Driven ◽  
Difficult Challenge ◽  
Splitting System ◽  
Pec Water Splitting

Visible-light-driven photoelectrochemical (PEC) and photocatalytic water splitting systems featuring heterogeneous semiconductor photocatalysts (oxynitrides, oxysulfides, organophotocatalysts) signify an environmentally friendly and promising approach for the manufacturing of renewable hydrogen fuel. Semiconducting electrode materials as the main constituents in the PEC water splitting system have substantial effects on the device’s solar-to-hydrogen (STH) conversion efficiency. Given the complication of the photocatalysis and photoelectrolysis methods, it is indispensable to include the different electrocatalytic materials for advancing visible-light-driven water splitting, considered a difficult challenge. Heterogeneous semiconductor-based materials with narrower bandgaps (2.5 to 1.9 eV), equivalent to the theoretical STH efficiencies ranging from 9.3% to 20.9%, are recognized as new types of photoabsorbents to engage as photoelectrodes for PEC water oxidation and have fascinated much consideration. Herein, we spotlight mainly on heterogenous semiconductor-based photoanode materials for PEC water splitting. Different heterogeneous photocatalysts based materials are emphasized in different groups, such as oxynitrides, oxysulfides, and organic solids. Lastly, the design approach and future developments regarding heterogeneous photocatalysts oxide electrodes for PEC applications and photocatalytic applications are also discussed.

Fabricating highly efficient heterostructured CuBi2O4 photocathodes for unbiased water splitting

2020 ◽  
Vol 8 (5) ◽  
pp. 2498-2504 ◽  
Author(s):  
Sabiha Akter Monny ◽  
Lei Zhang ◽  
Zhiliang Wang ◽  
Bin Luo ◽  
Muxina Konarova ◽  
...  
Keyword(s):  
Water Splitting ◽  
Photocurrent Density ◽  
Onset Potential ◽  
Highly Efficient ◽  
Splitting System

Efficient CuBi2O4 based photocathode with large onset potential (1.1 VSHE) and high photocurrent density (1.87 mA cm−2 at 0.6 VSHE) has been fabricated for constructing the unbiased water splitting system with the suitable photoanode.

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