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Proton Exchange Membrane Water Electrolysis
Published in Lei Zhang, Hongbin Zhao, David P. Wilkinson, Xueliang Sun, Jiujun Zhang, Electrochemical Water Electrolysis, 2020
Zhao Jin, Shuai Hou, Zhaoyan Luo, Rongpeng Ma, Yang Li, Yibo Wang, Junjie Ge, Changpeng Liu, Wei Xing
The oxygen evolution reaction (OER) is a counter electrode reaction occurring in electrolyzers. The OER is more challenging because the OER is a four electron-proton reaction way, while the HER is a two electron-transfer reaction, and, hence, the OER requires a higher energy (higher overpotential) to overcome the kinetic barrier of the OER to occur. In the OER reaction process, it requires the distribution of four redox processes over a narrow potential range, the coupling of multiple protons and electron transfers, and the formation of two oxygen-oxygen bonds. The OER reaction is also very important for recharging of fuel cells and metal–air batteries. Currently, several Ir-/Ru-based metal oxides as the HER and OER catalysts are required to catalyze the OER reaction in acidic media. However, the high cost, scarcity, and low durability of these noble metals restrict their wide utilization. Therefore, a substantial research effort has been devoted to developing active, stable, and cost-effective catalysts for oxygen evolution reaction. Although it is still extremely desirable, it remains the huge challenge for overall water splitting.
Biohydrogen Production by Photobiological Processes
Published in Debabrata Das, Jhansi L. Varanasi, Fundamentals of Biofuel Production Processes, 2019
Debabrata Das, Jhansi L. Varanasi
In oxygenic environments, the electrons needed for H2 production are derived from water by the light-induced water oxidation reaction of the photosynthetic organisms, which leads to oxygen evolution (Equation 7.1): () 2H2O→O2+4H++4e−
Highly active and stable synergistic Ir–IrO2 electro-catalyst for oxygen evolution reaction
Published in Chemical Engineering Communications, 2018
Zhen-Hua Zhou, Wei Sun, Waqas Qamar Zaman, Li-Mei Cao, Ji Yang
The electrochemical oxygen evolution reaction (OER) has extensive applications concerning clean energy technologies, including rechargeable metal–air batteries (Liu et al., 2015), electrolysis cells (Radjenovic and Sedlak, 2015), and solar fuel production (Zhen, 2016). Developing OER reaction with higher efficiency remains a challenge due to the associated process complexities, with four-electron oxidation, that impose considerable electrochemical overpotential (η), and therefore being kinetically sluggish is accompanied with substantial energy loss (Gao et al., 2014; Hong et al., 2015). OER catalysts in alkaline and neutral electrolysis conditions are distinguished for being non-noble, long-term stable, and relatively lower in cost (Li et al., 2016; Wang et al., 2015). However, non-noble metal electrocatalysts for OER in acidic media with high activity and stability are essentially rare (Popczun et al., 2014) duo to the acid-aggressive and strong corrosive conditions. Moreover, elevated potentials during OER are found to intensify the dissolution (Cherevko et al., 2015), which are detrimental for high electric charge exchange situation. On account of the efficiency and durability, OER electrocatalysts for acid environment are commonly inseparable from noble metal oxides.
Biomass derived metal free hierarchical porous activated carbon for efficient oxygen evolution reaction
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Sujit Kumar Guchhait, Debanjan Sutradhar, Rajib Nandi, Anil Kumar Sarma
The rapid industrial growth, fast development of society, and explosion of population have led to the amplification of energy consumption and decrease in fossil fuels (i.e. oil, coal, natural gas, etc.) as well as environment pollution, threatening the sustainability of living standards. Due to this, efforts to develop energy storage and conversion technologies for clean and renewable energy, such as solar energy, wind power, hydroelectricity, electrochemical water splitting, aqueous Zn-CO2 battery for CO2 power conversion, and electrochemical N2 reduction reaction, have been increasing intensively in recent days (Gonçalves et al. 2021; Pareek et al. 2020; Hao et al. 2022, 2022; Wen et al. 2021). Among different energy technologies, electrochemical water splitting is a sustainable, cost-effective process to generate clean energy as well as O2 and H2, which can be utilized as a renewable and viable energy source (Pareek et al. 2020). Four-electron transfer process is involved in the oxygen evolution reaction (OER) during water splitting. These four electrons in the anodic reaction with current density 10 mA/cm2 are generally thermodynamically sluggish (Hu, Zhang, and Gong 2019). Therefore, creating effective and reliable electrocatalysts is necessary to reduce the energy barrier and encourage OER during electrochemical water oxidation. Ruthenium (Ru), iridium (Ir), rhenium (Rh), and their oxides/composites are considered state-of-the-art material for showing highly efficient activity toward oxygen evolution (Majidi et al. 2020). There are various transition-metal carbide and binary metal sulfide electro-catalysts as reported for electrochemical hydrogen evolution reaction (HER) and OER (Zhang et al. 2020, Hao et al. 2022, Zhu et al. 2021). However, the main obstacles for commercialization of these materials are their expensive price, low availability and low stability (Wang et al. 2020). Therefore, it will always be desirable to produce an effective, affordable, durable electrocatalyst that can improve catalytic performance toward OER. Among the novel carbon electrode materials, carbon nanotubes (Mohideen, Liu, and Ramakrishna 2020), 3D graphitic carbons (Jorge et al. 2020), graphene (Dai 2017), mesoporous carbon (Long term stability constraints), activated carbon (AC) (Baas-López et al. 2021), and so on, have received huge attention due to their exceptional and wide properties, that is, natural abundance, unique structure, active functional surfaces, excellent electronic conductivity, and excellent cycling stability. Due to their renewable nature, efficiency, and environmental friendliness, different biomass have lately attracted attention as feasible biomass feedstocks for the preparation of these carbonaceous materials for electrochemical applications (Kaur, Verma, and Sekhon 2019).