Enthralling Anodic Protection by Molybdate on High-Entropy Alloy-Based Electrocatalyst for Sustainable Seawater Oxidation.

Efficient and sustainable seawater electrolysis is still limited due to the interference of chloride corrosion at the anode. The designing of suitable electrocatalysts is one of the crucial ways to boost electrocatalytic activity. However, the approach may fall short as achieving high current density often occurs in chlorine evolution reaction (CER)-dominating potential regions. Thereby, apart from developing an OER-active high-entropy alloy-based electrocatalyst, the present study also offers a unique way to protect anode surface under high current density or potential by using MoO4 2- as an effective inhibitor during seawater oxidation. The wide variation of d-band center of high-entropy alloy-based electrocatalyst allows great oxygen evolution reaction (OER) proficiency exhibiting an overpotential of 230 mV at current density of 20 mA cm-2. Besides, the electrocatalyst demonstrates impressive stability over 500 h at high current density of 1 A cm-2 or at a high oxidation potential of 2.0 V versus RHE in the presence of a molybdate inhibitor. Theoretical and experimental studies reveal MoO4 2- electrostatically accumulated at anode surface due to higher adsorption ability, thereby creating a protective layer against chlorides without affecting OER.

New age chloride shielding strategies for corrosion resistant direct seawater splitting.

Electrocatalytic direct seawater splitting is considered to be one of the most desirable and necessary approach to produce substantial amount of green hydrogen to meet the energy demand. However, practical seawater splitting remains far-fetched due to the electrochemical interference of multiple elements present in seawater, among which chlorine chemistry is the most aggravating one, causing severe damages to electrodes. To overcome such limitations, apart from robust electrocatalyst design, electrolyte engineering along with in depth corrosion engineering are essential aspects, which needs to be thoroughly judged and explored. Indeed, extensive studies and various approaches including smart electrolyzer design have been attempted in the last couple of years on this matter. The present review offers a comprehensive discussion on various strategies to achieve effective and sustainable direct seawater splitting, avoiding chlorine electrochemistry to achieve industry-level performances.

Mott-Schottky heterojunction of Se/NiSe2 as bifunctional electrocatalyst for energy efficient hydrogen production via urea assisted seawater electrolysis.

Seawater electrolysis is considered to be very challenging owing to competitive reaction kinetics in between oxygen evolution reaction and corrosive chlorine evolution reaction mechanism at anode, especially towards higher current density. The present work, proposes a promising and energy efficient strategy by coupling seawater splitting with urea decomposition lowering oxidation potential and thereby avoiding hypochlorite formation even at high current density. The rational design of Mott-Schottky heterojunction of Se/NiSe2 as electrocatalyst is considered to be highly effective in this regard. The developed Se/NiSe2 exhibits extraordinary energy saving for alkaline seawater splitting in presence of urea. The Se/NiSe2/NF || Se/NiSe2/NF electrolyser configuration achieved 10 and 50 mAcm-2 current densities with cell voltage of 1.59 and 1.70 V along with outstanding operational durability over 50 h. The large number of carrier density generates by synergistic self-driven electron transfer from Se to NiSe2 at the heterojunction, unique metallic properties of selenium (Se), and also abundance accessible reactive edges on the porous channel of Ni foam are believed to be the reason behind such enhanced electrocatalytic activities towards urea oxidation reaction and hydrogen evolution reaction offering unique and much energy saving approach for alkaline-urea-seawater electrolysis avoiding hypochlorite formation.

Cobalt chromium vanadium layered triple hydroxides as an efficient oxygen electrocatalyst for alkaline seawater splitting.

Cobalt chromium vanadium layered triple hydroxides have been identified as a promising electrocatalyst for seawater splitting. The insertion of vanadium as a third metal into cobalt chromium layered double hydroxides not only adds extra cationic active sites but also facilitates electronic transition from Co(II) to V(V) boosting the OER activity and suppressing the CER.

Bismuth iron molybdenum oxide solid solution: a novel and durable electrocatalyst for overall water splitting.

The drive for finding active bifunctional electrocatalysts for efficient overall water splitting continues in order to extract energy in the form of hydrogen as a clean fuel. Bismuth iron molybdenum oxide solid solution, composed of orthorhombic Bi2MoO6 as the major component and monoclinic Bi3(FeO4)(MoO4)2 as the minor component, has been identified as a potential electrocatalyst for the first time.