Hydrothermally Derived Hierarchical CuO Nanoflowers as an Efficient Photocatalyst and Electrocatalyst for Hydrogen Evolution

Abstract

Fabrication of an efficient, economic and earth‐abundant nanocatalyst for H2 production is the centre of attraction in renewable energy technology, but it is still a massive task. In present work, we report a facile modified hydrothermal route to synthesize hierarchical CuO nanoflowers as a noble metal free, proficient photo and electrocatalyst for hydrogen generation. Electrochemical studies were performed over as‐synthesized CuO nanoflowers in both acidic and alkaline medium to record both HER and OER responses. An enhanced HER activity with an overpotential of 1.02 V at −10 mA/cm2 cathodic current density and OER activity with an onset potential at around 1.01 V, respectively, superior to the art of HER and OER bi‐catalyst. Photocatalytic H2 evolution performance exhibits the significant production of 16 mmol/g−1cat in time interval of 8 hours in the presence of Na2S/Na2SO3 sacrificial agent.

Oxide based Heterostructured Photocatalysts for CO2 Reduction and Hydrogen Generation

“…Schottky junctions are the metal‐semiconductor heterojunctions which surface due to gradient between their Fermi levels. This gradient develops the built‐in electric field which subdues the recombination rate efficiently, thus facilitating the photocatalytic operations [123–125] . The schematic representation of schottky junctions is diagrammatically shown in Figure 9(d).…”

“…This gradient develops the built-in electric field which subdues the recombination rate efficiently, thus facilitating the photocatalytic operations. [123][124][125] The schematic representation of schottky junctions is diagrammatically shown in Figure 9(d). The different types of heterojunctions employed in the few oxide based heterostructured photocatalysts along with the mechanistic approach embraced during their photocatalytic CO 2 reduction and H 2 evolution are revealed in Table 4.…”

ZrO2/CeO2-Heterostructured Nanocomposites for Enhanced Carbon Monoxide Gas Sensing

“…9,10 Nowadays, metal oxide semiconductors with various morphologies and structures have been synthesized by different methods, such as nanosheets, 11 nanocubes, 12 nanowires, 13 nanorods, 14 nanospheres, 15 nanoplates, 16 and nanoflowers. 17,18 Further, besides these, hollow nanostructures have revealed immense potential in the field of gas sensors and have attracted strong attention due to their peculiar properties, like enhanced surface areas, good interfacial charge transfer efficiency, increased surface permeability, 19−22 and low density. However, the synthesis of hollow nanostructures is a very tedious process which relies on some complicated template routes in which soft or hard templates have been used, such as carbon spheres, silica, gas bubbles, and emulsion droplets.…”

“…Semiconductor metal oxides are emerging as predominant gas sensing materials due to their unique physical and chemically tunable properties in the applications of detecting deleterious, toxic, pollutant, and explosive gases. − The inherent properties of metal oxides along with their composites, like the porous structure which is expressed in the form of a high specific surface area and tunable band gaps with unique semiconducting properties, make them compelling candidates for gas sensing applications. − Metal oxide nanomaterials, in combination with the general benefits, the addition of metal oxides into metal oxide nanomaterials is a new approach which has improved the sensing performance dramatically due to the synergistic effects of these materials. In the case of semiconductor oxides, the structure and surface morphology play a profound role in the sensing properties of gas due to the sensing mechanism, in which the oxygen adsorption and the reaction of oxygen with test gas molecules on the surface of metal oxides correlate with the resistance change. , Nowadays, metal oxide semiconductors with various morphologies and structures have been synthesized by different methods, such as nanosheets, nanocubes, nanowires, nanorods, nanospheres, nanoplates, and nanoflowers. , Further, besides these, hollow nanostructures have revealed immense potential in the field of gas sensors and have attracted strong attention due to their peculiar properties, like enhanced surface areas, good interfacial charge transfer efficiency, increased surface permeability, − and low density. However, the synthesis of hollow nanostructures is a very tedious process which relies on some complicated template routes in which soft or hard templates have been used, such as carbon spheres, silica, gas bubbles, and emulsion droplets.…”

Graphene-Based Derivatives Heterostructured Catalytic Systems for Sustainable Hydrogen Energy via Overall Water Splitting

“…Expensive metal catalysts are affected by their shortage and comparatively low stability, which hinder their general use in large-scale applications. Consequently, catalysts with higher activity and lower cost are imperatively needed for large-scale practical applications [57]. Table 1 includes the advantages and disadvantages of the photochemical, electrochemical and photoelectrochemical methods.…”