Active and stable graphene supporting trimetallic alloy-based electrocatalyst for hydrogen evolution by seawater splitting

Mini Review on Electrocatalyst Design for Seawater Splitting: Recent Progress and Perspectives

“…In comparison to acid or neutral electrolytes, an alkaline electrolyte has attracted great interest, owing to its actual maneuverability. As shown in Figure , the oxygen evolution and chlorine evolution equilibrium potentials are only different by 130 mV at pH 0, and OER is a complex four-electron oxidation with slow reaction kinetics and higher overpotential, while CER is a more facile two-electron transfer reaction with faster reaction kinetics. − However, the equilibrium potential of chlorine evolution does not depend upon the pH value; under alkaline conditions, the voltage gap between chloride oxidation and oxygen formation increases to 480 mV, even if the hypochlorite formation can still compete with OER, and operating at pH > 7.5 is usually used as a general design criterion for non-noble metals in seawater electrolysis. , During the past decades, although tremendous effort has been put into the preparation of high-efficiency water splitting electrocatalysts, the direct electrolysis of seawater has been seldom reported and exhibits poor efficiency when applied to industrial conditions. To avoid the hypochlorite formation, high-efficiency OER catalysts are required for great selectivity toward alkaline seawater electrolysis.…”

“…23−25 However, the equilibrium potential of chlorine evolution does not depend upon the pH value; under alkaline conditions, the voltage gap between chloride oxidation and oxygen formation increases to 480 mV, even if the hypochlorite formation can still compete with OER, and operating at pH > 7.5 is usually used as a general design criterion for non-noble metals in seawater electrolysis. 26,27 During the past decades, although tremendous effort has been put into the preparation of high-efficiency water splitting electrocatalysts, the direct electrolysis of seawater has been seldom reported and exhibits poor efficiency when applied to industrial conditions. To avoid the hypochlorite formation, high-efficiency OER catalysts are required for great selectivity toward alkaline seawater electrolysis.…”

Nanoengineered, Mo-Doped, Ni3S2 Electrocatalyst with Increased Ni–S Coordination for Oxygen Evolution in Alkaline Seawater

“…13,14 Therefore, one of the important general design criteria of noble-metal free catalysts for seawater electrolysis is an operating pH exceeding 7.5. 15,16 In addition, the formation of insoluble calcium and magnesium hydroxides on the electrode surface due to local fluctuations in pH and the corrosion caused by metal chlorination reactions both severely restrict the efficiency and long-term stability of various advanced catalysts. 17,18 Although research on seawater electrolysis was carried out by Bennett et al as early as 1980, 19 the development of OER catalysts toward seawater electrolysis has been very slow due to the challenges mentioned above.…”

“…The oxidation of chloride, which involves the transfer of fewer electrons than the OER, is kinetically more favorable than the OER but has a higher thermodynamic potential than the OER. , In alkaline electrolytes, chloride ions are oxidized to hypochlorite (Cl – + 2OH – = ClO – + H 2 O + 2e – ); under these conditions, the thermodynamic potential maximized difference remains between the chloride oxidation and the OER, and electrocatalysts for OER can operate under an overpotential of up to approximately 490 mV without any oxidation of chloride ions. , Therefore, one of the important general design criteria of noble-metal free catalysts for seawater electrolysis is an operating pH exceeding 7.5. , In addition, the formation of insoluble calcium and magnesium hydroxides on the electrode surface due to local fluctuations in pH and the corrosion caused by metal chlorination reactions both severely restrict the efficiency and long-term stability of various advanced catalysts. , …”

Cobalt Phosphates Loaded into Iodine-Spaced Reduced Graphene Oxide Nanolayers for Electrochemical Measurement of Superoxide Generated by Cells

“…In recent years, reduced graphene oxide (rGO), a single-layer carbon atom sheet nanomaterial, possesses superior conductivity, large surface area, and high reactivity and has been used successfully to construct various electrochemical devices including electrochemical sensors for detection of various bioactive molecules . With modification or hybridization approaches for different nanocomposites, rGO shows significant synergistic effects in sensing platforms. , For instance, the complex of rGO and gold (Au) nanoparticles has been used to construct a specific NO sensing membrane with short response time.…”