Developments and Perspectives on Robust Nano‐ and Microstructured Binder‐Free Electrodes for Bifunctional Water Electrolysis and Beyond

Abstract

Ni, Fe, and Cu foams to form robust binder-free electrodes for high-performance electrocatalytic reactions. [55][56][57][58][59] Interestingly, multidimensional electrocatalysts grown at the nanoscale on a range of current collectors, namely substrates and will benefit from a strong adhesion with the current collector to avoid catalyst delamination, limited active sites, and charge transfer blockage to enhance catalytic reactions (Figure 1b-d). [9,[60][61][62][63][64] Key Prospects, Insights, and the Dynamic Properties of Nano-and Microstructured Binder-Free Electrocatalysts and Their Direct Impact on Electrochemical ReactionsWater splitting has become one of the most important technologies to produce hydrogen (H 2 ) in high purity form. Water splitting includes two half-reactions, namely the cathodic HER and anodic OER. [8,65] Generally, the electrocatalytic performance and activity are highly sensitive to local reaction conditions and is largely valued by the energy required for adsorption/desorption of reaction intermediates and the rupture/creation of chemical bonds. Hence, the conventional powder form of precious metals such as Pt/C for the HER and RuO 2 or IrO 2 for the OER are considered ideal electrocatalysts. [66] In addition, several nonprecious 1D, 2D, and 3D nano-and microstructured powder catalysts such as MoS 2 , WS 2 , Ni 3 S 2 , NiCo 2 S 4 are also of interest for the HER and OER reactions. [54,[67][68][69][70][71][72][73][74] However, for commercial purposes and practical applica-

Recent advances in nanostructured heterogeneous catalysts for N-cycle electrocatalysis

“…Furthermore, building a binder-free electrode for N-cycle catalysis would be a good option. Binder-free electrodes (for example, nanoarray, membrane, and self-standing films) have two advantages over traditional powder electrodes [129]. (i) The rich structural voids between neighboring nanostructures and the large surface area of the binder-free architecture allow for well-exposed active sites and a sufficient surface-electrolyte contact.…”

MOF-derived nanoarrays as advanced electrocatalysts for water splitting

“…To date, there have been some reviews on MOF-derived electrocatalysts 2,5,8,9,[13][14][15][16][17][18] and self-supported nanoarray electrocatalysts. 11,12,[19][20][21] However, none of them have specially focused on MOF-derived nanoarrays for electrocatalytic water splitting processes. With the advancement of various nanotechnologies and applications, remarkable progress in this field has been made in recent years.…”

Insights into Heterogeneous Catalysts under Reaction Conditions by In Situ/Operando Electron Microscopy

“…Electrocatalytic or photocatalytic water splitting (OER, HER) is an important pathway toward clean hydrogen production. [255][256][257][258] HER is the reaction at the cathode to produce H 2 ; OER is the reaction at the anode to produce O 2 . One of the critical barriers is the sluggish reaction kinetics of OER and HER leading to high overpotentials.…”