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Over the past decades, tremendous effort has been made to enhance the water‐splitting via fabricating eco‐friendly electrocatalyst with increased conductivity, and large number of accessible active sites in lab scale. However, the development of earth abundant efficient electrocatalyst with superior activity for ‐seawater‐splitting remains a great challenge for the researchers. In this regard, self‐supported catalysts are found to be the most promising candidates, they have the features of increased loading, superior adhesion, rapid mass and charge transfer, and easy wettability for large scale hydrogen production via electrochemical seawater splitting. This review investigates different fabrication processes for the self‐supported catalyst, emphasizing their distinct characteristics that contribute to improved activity. Furthermore, we provided a detailed elucidation of the procedure and characteristics of seawater splitting, emphasizing the most recent progress in the creation of self‐supportive catalyst for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and bifunctional activity. We have also examined the current barriers and potential prospects for advancing the utilization of self‐supported catalysts in the process of seawater splitting. [ABSTRACT FROM AUTHOR]

Abstract Over the past decades, tremendous effort has been made to enhance the water‐splitting via fabricating eco‐friendly electrocatalyst with increased conductivity, and large number of accessible active sites in lab scale. However, the development of earth abundant efficient electrocatalyst with superior activity for ‐seawater‐splitting remains a great challenge for the researchers. In this regard, self‐supported catalysts are found to be the most promising candidates, they have the features of increased loading, superior adhesion, rapid mass and charge transfer, and easy wettability for large scale hydrogen production via electrochemical seawater splitting. This review investigates different fabrication processes for the self‐supported catalyst, emphasizing their distinct characteristics that contribute to improved activity. Furthermore, we provided a detailed elucidation of the procedure and characteristics of seawater splitting, emphasizing the most recent progress in the creation of self‐supportive catalyst for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and bifunctional activity. We have also examined the current barriers and potential prospects for advancing the utilization of self‐supported catalysts in the process of seawater splitting.

To capitalize the improved electrical contact feature, a self-supported hybrid binary/ternary copper and zinc oxides (i.e., ZnO–Cu 2 O and Cu 2 O–ZnO–CuO) nanostructures have been generated via a simple potentiostatic mode of anodaization on alpha brass in an alkaline medium. The catalyst nanostructuring i.e., wheat-grain-like to nanograss type structure has improved the mass transport, sluggish kinetics of methanol electrooxidation reaction process, and hindered the competitive oxygen evolution reaction (OER) of direct methanol fuel cell. The catalytic poisoning phenomenon has not been noticed due to two different reaction processes in two potential regions. Interestingly, a significant reduction in overpotential (η 10 mAcm − 2 OER − CH 3 OH ) has been noticed for S125@A1 and S125@A2 samples i.e., 236 mV and 350 mV, respectively. The enhancement of current density has been explained through inductive circuit perspective. So, the present study provides a better insights to design and utilize non-precious metal/alloy based catalyst with hindered OER and enhanced methanol electrooxidation reaction activity. Enhanced methanol electrooxidation reaction with hindered competitive oxygen evolution reaction on engineered anodized brass. [Display omitted] • Self-supported hybrid ZnO-Cu 2 O and Cu 2 O-ZnO-CuO catalysts. • Generation of electrocatalysts via potentiostatic anodization process. • Enhanced methanol electrooxidation with hindered OER on as-anodized brass. • S125@A2 shows overpotential η 10 mAcm − 2 OER − CH 3 OH : 350 mV vs Hg/HgO and excellent stability. • Enhanced current density 112 mAcm-2 at +0.65 V vs Hg/HgO (i.e., 1.574 V vs RHE). [ABSTRACT FROM AUTHOR]

Summary: Alkaline oxygen evolution reaction (OER) electrocatalysts have been widely studied for improving the efficiency and green hydrogen production through electrochemical water splitting. Currently, iron‐doped nickel‐LDHs (NF‐LDHs) are regarded as the benchmark electrocatalyst for alkaline OER, primarily owing to the physicochemical synergetic effects between Ni and Fe. Here, the third element addition into NF‐LDHs is designed to further enhance the electrocatalytic performance through the modulation of electronic property. Cu‐doped NF‐LDHs (NFC‐LDHs) are developed with the self‐supported structure on porous supports. NFC‐LDHs can be grown on carbon cloth (CC) in an intriguing 2D nanosheet structure, wherein the surface electronic configuration is suitably modulated by interactions among Ni‐Fe‐Cu. Importantly, activation energy for OER can be lowered by adding Cu into NF‐LDHs. Thereby, the NFC‐LDHs exhibited enhanced OER activity and improved stability than those of nickel‐LDHs (Ni‐LDHs) and NF‐LDHs. For NFC‐LDHs, small overpotentials of only 230 and 250 mV yield current densities of 50 and 100 mA cm−2, respectively. In addition, excellent electrochemical stability is demonstrated during long‐term OER tests without any degradation demonstrating no dissolution of active metals water electrolysis due to synergetic effects among Ni‐Fe‐Cu. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mixed metal oxide & borate heterostructure over exfoliated graphite foam is presented. • Nitrogen doped support and supported catalyst interaction leads to excellent catalytic activity. • Large enhancement in OER catalytic activity due to electronic tuning of support via N-doping. • Outstanding durability at high current density 300 mA cm−2 over 10 h is demonstrated. Support-catalyst interface plays a critical role in electrocatalytic processes as the rates of involved reactions are directly linked with the interfacial charge transfer efficiency. Here, we are presenting nitrogen doped exfoliated graphite foil (NGF) as the 3D support which offers electronically coupled interface to catalytic heterostructure comprises of nickel-iron based oxide and its borate. As developed hybrid (NGF/NiFe/Borate) show excellent oxygen evolution reaction (OER) under alkaline condition with low overpotential of 281 mV at current density of 10 mA cm−2 and Tafel slope 62 mv dec−1. The results beat most nonprecious metal catalysts and noble commercial IrO 2 deposited over same NGF substrate with outstanding long-term durability over 10 h at high current density 300 mA cm−2. Efficient electron injection from NGF support and its low resistance leads to enhancement in current density by more than 136 % at operative potential of 1.55 V, in comparison to un-doped exfoliated graphite foil support. Beside electronically tuned support, high catalytic efficiency is also linked with planner growth of borate nanosheets that helps in fast interfacial charge transfer in its transverse direction to the catalytic site. Our work highlights the importance of electronic tuning of catalyst support to enhance the performance of supported borate catalyst and to rationally design low cost, highly active OER catalyst. [ABSTRACT FROM AUTHOR]

• Highly efficient and recyclable catalysts with atomically dispersed catalytic sites. • Selective and effective mono- N -methylation of nitroarenes via one pot tandem reaction. • Using methanol as green carbon source and water is the only byproduct. • Avoiding the usage of toxic reagents. A series of N -heterocyclic carbene-iridium (NHC-Ir) coordination assemblies based on bis-pyrenoimidazolium salts are prepared, and shown to function as efficient solid molecular catalysts in selective mono- N -methylation of nitroarenes with methanol under mild conditions. The atomically dispersed active Ir(I) centers and the large π-conjugation rings endow the solid catalysts with an exceptionally high activity and selectivity for a broad substrate scope. Such solid NHC-Ir coordination assemblies are robust, which can be easily recovered and reused more than 10 runs without significant loss of their catalytic activity and selectivity. When combined with a subsequent formylation using the same solid catalysts under ambient conditions, this novel protocol can afford diverse formamides in excellent yields, further highlighting the applicability of the present solid catalysts for an efficient diversification of nitroarenes to a broad number of functional amines. [ABSTRACT FROM AUTHOR]

To achieve efficient water splitting, it is essential to develop catalysts with high electrochemical performance, enhanced durability and tunable properties. Most of the transition metal-based catalysts employed for the water splitting have been fabricated on the solid-electrode support by using binder, which decreases the activity and durability of the catalyst system. In this respect, self-supported metal organic framework (MOF) derived catalysts have been introduced with enhanced catalytic activity and mechanical stability for the electrochemical water splitting. The self-supported MOF derived catalysts exhibit improved electronic conductivity, high electrochemical surface area, enhanced mechanical stability and strong catalyst-support interaction. Moreover, these catalysts possess highly porous and hollow structure with designed morphology and multi-metallic composition. Recently, a tremendous effort has been provided to explore this newly growing field and new dimensions and directions have been achieved. Looking at this point, we have described here the basic principles of catalyst design from self-supported MOF, structural and interface engineering by controlling the electronic structure of the catalysts to improve the water splitting activity. In addition, the challenges and difficulties associated with this field have been pointed out and addressed for the future progress in this field. [ABSTRACT FROM AUTHOR]

Designing a self‐supported and binder‐free electrocatalyst for electrochemical detection of bio‐analytes is an intriguing area of research on electrochemical sensors. Herein, glassy carbon GC and graphene (Gr) were transformed to self‐supported and binder‐free electrocatalysts (N−GCE and N−Gr) for metal‐free and non‐enzymatic H2O2 detection by a simple electrochemical incorporation of nitrogen on their surfaces. The presence of nitrogen and its functional groups in N−GCE and N−Gr was confirmed by Raman, X‐ray photoelectron spectroscopy and cyclic voltammetry. We found that the nitrogen incorporated surfaces, N−GCE and N−Gr show enhanced electrocatalytic activity compared to the oxygen incorporated surfaces, O−GCE and O−Gr, and plain GCE and Gr. The apparent electron transfer rate constant, ka of N−GCE and N−Gr increased significantly after nitrogen incorporation. The N−GCE and N−Gr show enhanced electrochemical performance towards H2O2 in terms of sensitivity, selectivity, stability, and reusability. The rate determining step of H2O2 reduction at N−GCE and N−Gr was determined by rotating disc electrode experiments. Also, N−GCE and N−Gr are shown to be potential candidates for the detection of H2O2 in real samples like urine and milk. The hidden potential of the method reported is that it can be extended to design many novel electrocatalytic materials simply by selecting a proper allotrope of carbon from the wide list of carbon allotropes. The electrocatalytic activity of sp2 carbon surfaces of glassy carbon (GC) and graphene electrodes are modulated by electrochemical nitrogen incorporation. The electrochemical incorporation of nitrogen into the GC and graphene electrodes turns them into self‐supported and binder‐free electrocatalysts for enhanced detection of H2O2 in PBS and in the real samples urine and milk. [ABSTRACT FROM AUTHOR]

A metal-coordination-driven self-assembly using the predesigned building block has been developed. Herein, the catalytic active NHC–Cu(I) units were introduced into the terpyridine metal coordination polymers. The self-assembled architecture, as a heterogeneous catalyst, was successfully used to catalyze the A3-coupling reaction of aldehyde, alkyne, and amine and Huisgen 1,3-dipolar cycloaddition reaction of azide and alkyne in high yields. [ABSTRACT FROM PUBLISHER]

Electrochemical water splitting is considered to be one of the most promising strategies for clean and efficient hydrogen production. In this paper, an in-situ growth of iron-nickel phosphide on nickel foam (FeNiP x /NF) is demonstrated as a self-supported ternary catalyst for electrochemical water splitting. The FeNiP x /NF were prepared by a thermo-reaction between NaH 2 PO 2 and NiFe hydroxide precursors that are in situ grown on Ni foam via a simple chemical precipitation reaction. In this newly proposed method, the nickel foam not only acts as an electrode substrate, but also serves as a slow-release Ni source in the reaction due to its oxidation by Fe 3+ in solution. Benefiting from collaborative advantages of bimetallic composite, metallic phosphide, and unique electrode fabrication, the FeNiP x /NF exhibits extraordinarily high activities for both OER and HER with low overpotentials of of 192 and 106 mV at 10 mA cm −2 , 236 and 161 mV at 100 mA cm −2 , respectively. The voltage during the galvanostatic electrolysis is well maintained for almost 400 h without any visible elevation, representing the few most stable noble-metal-free catalysts for water splitting. [ABSTRACT FROM AUTHOR]

Since chiral coordination complexes have a broad scope for asymmetric synthesis, their immobilization has been the subject of intensive research. Indeed, the immobilization of chiral catalysts is an appealing approach to solve problems such as product contamination or catalyst reuse. Numerous approaches have been developed and despite promising results each immobilization technique displays several strengths and limitations that make them highly specific. During the last years, dynamic self-supported catalysis has emerged as an alternative and new strategy to circumvent some limitations of classical immobilized catalysts. In such system, a metal-organic self-assembly is in equilibrium with discrete monomeric active species, a case that offers exciting opportunities for catalysis. Recent work in this area shows that these systems can compete with their homogeneous counterparts. This review highlights the recent developments in the growing field of dynamic self-supported asymmetric catalysis. [ABSTRACT FROM AUTHOR]

In this work, for the first time, a cobalt carbonate hydroxide (Co(CO3)0.5(OH)⋅0.11 H2O) nanowire array on Ti mesh (CHNA/Ti) was applied to drive the dehydrogenation of alkaline NaBH4 solution for on-demand hydrogen production. Compared with other nanostructured Co-based catalyst systems, CHNA/Ti can be activated more quickly and separated easily from fuel solutions. This self-supported cobalt salt nanowire array catalyst works as an efficient and robust 3D catalyst for the hydrolysis reaction of NaBH4 with a hydrogen generation rate of 4000 mL min−1 gCo−1 and a low apparent activation energy of 39.78 kJ mol−1 and offers an attractive system for on-demand hydrogen generation. [ABSTRACT FROM AUTHOR]

The hetero-phase Mo 2 C-CoO@ N -CNFs film is electrospun and exhibit remarkable HER and OER properties as a self-supported bi-functional catalyst towards overall water splitting. [Display omitted] • A self-standing Mo 2 C-CoO@ N -CNFs film catalyst is electrospun for both HER and OER. • Nanoscale hetero-phase Mo 2 C-CoO particles are well-distributed in N -doped carbon nanofiber film. • Mo 2 C-CoO@ N -CNFs film owns good wettability, multi-pore structure and high electrical conductivity/active sites. • The Mo 2 C-CoO hetero-phase accelerates the kinetics of HER and reduces energy barrier of OER. • The bi-function Mo 2 C-CoO@ N -CNFs-8 film displays superb catalytic for alkaline overall water splitting. It is an enormous challenge to develop low-cost non-noble metal bi-functional catalysts toward overall water splitting. The efficient water decomposition electrocatalysts need both intrinsic activities determined by electronic structure and superb mass transfer ability. For this, in the contribution, an efficient self-supported bi-functional catalyst, i.e. , nanoscale hetero Mo 2 C-CoO encapsulated in N -doped carbon nanofibers (Mo 2 C-CoO@ N -CNFs), is designed and fabricated with facile electrospinning avenue. Density functional theory and electrochemical investigation manifest that the synergistic effect of bimetallic Mo/Co accelerates kinetics of hydrogen evolution reaction (HER) and lowers the energy barrier of oxygen evolution reaction (OER). Thanks to the structural and compositional merits, the optimized integrated Mo 2 C-CoO@ N -CNFs film demonstrates remarkable catalytic activities in both OER and HER, and renders a current density of 10 mA cm−2 at 1.56 V when used for alkaline whole water cracking. The design concept here provides insights for future rational construction of advanced water decomposition catalysts. [ABSTRACT FROM AUTHOR]

The study of N-heterocyclic carbenes (NHCs) as organocatalysts has proliferated in recent years, and they have been found to be useful in a variety of reactions. In an attempt to further expand their utility and to study their recyclability, we designed and synthesized a series of self-supported NHCs in which the catalytic carbene groups form part of a densely functionalized polymer backbone, and studied them as organocatalysts. Of the self-Supported NHCs examined, a benzimidazole derived polymer with flexible linkers connecting the catalytic groups was found to be the most efficient organocatalyst in a model benzoin condensation reaction, and thus it was used in a variety of such reactions, including some involving catalyst recycling. Furthermore, it was also used to catalyze a set of redox esterification reactions involving conjugated unsaturated aldehydes. In all of these reactions the catalyst afforded good yield of the desired product and its polymeric nature facilitated product purification.