An effcient electrocatalytic Pd system, prepared via the AACVD method, is presented executing high activity water oxidation at 1.43 V vs RHE; η = 200 mV while exceeding the benchmark performance of IrO2.

Water oxidation catalysis is gaining more attention in recent times owing to its potential for solar and chemical energy conversion and for green fuel generation. The overwhelming hurdle in this quest is to develop a noble-metal-free, efficient, low overpotential water oxidation electrocatalyst exhibiting tremendous stability and to be obtained from earth-abundant materials. We show here unique copper-based water oxidation electrocatalyst derived from thin film Cu-colloidal nanoparticles and is highly efficient, robust for water oxidation. The catalyst advantageously exhibits nanobeads and nanorods type mixed morphological features with narrow size distribution. The onset for oxygen evolution reaction occurs at a small potential of 1.45 V RHE (η = 220 mV) which is the lowest observed relative to other copper-based materials. The catalyst also maintains remarkable stability during long-term water electrolysis experiments. Moreover, the catalyst shown to exhibit a high electroactive area with a Tafel slope of 52 mV dec 1À , high TOF of 0.81 s 1À and mass activity of 87 mA mg À 1 . Copper is an interesting material because it can also serve as CO 2 reduction catalysts at the cathode side. The straightforwardly prepared, handy, and inexpensive Cu-based electrocatalytic system is a flexible catalyst for electrooxidation of water and for chemical energy conversion and is an attractive alternative to Pt, Ir, and Ru based electrocatalysts obtained from expensive resources and tedious methods.

A sustainable future demands innovative breakthroughs in science and technology today, especially in the energy sector. Earth‐abundant resources can be explored and used to develop renewable and sustainable resources of energy to meet the ever‐increasing global energy demand. Efficient solar‐powered conversion systems exploiting inexpensive and robust catalytic materials for the photo‐ and photo‐electro‐catalytic water splitting, photovoltaic cells, fuel cells, and usage of waste products (such as CO2) as chemical fuels are appealing solutions. Many electrocatalysts and nanomaterials have been extensively studied in this regard. Low overpotentials, catalytic stability, and accessibility remain major challenges. Metal nanoclusters (NCs, ≤3 nm) with dimensions between molecule and nanoparticles (NPs) are innovative materials in catalysis. They behave like a “superatom” with exciting size‐ and facet‐dependent properties and dynamic intrinsic characteristics. Being an emerging field in recent scientific endeavors, metal NCs are believed to replace the natural photosystem II for the generation of green electrons in a viable way to facilitate the challenging catalytic processes in energy‐conversion schemes. This Review aims to discuss metal NCs in terms of their unique physicochemical properties, possible synthetic approaches by wet chemistry, and various applications (mostly recent advances in the electrochemical and photo‐electrochemical water splitting cycle and the oxygen reduction reaction in fuel cells). Moreover, the significant role that MNCs play in dye‐sensitized solar cells and nanoarrays as a light‐harvesting antenna, the electrochemical reduction of CO2 into fuels, and concluding remarks about the present and future perspectives of MNCs in the frontiers of surface science are also critically reviewed.

Electrochemical water splitting is economically unviable due to the sluggish kinetics of the anodically uphill oxygen evolution reaction (OER).