In this contribution we have developed TiO inverse opal based photoelectrodes for photoelectrochemical (PEC) water splitting devices, in which Au nanoparticles (NPs) and reduced graphene oxide (rGO) have been strategically incorporated (TiO@rGO@Au). The periodic hybrid nanostructure showed a photocurrent density of 1.29 mA cm at 1.23 V vs RHE, uncovering a 2-fold enhancement compared to a pristine TiO reference. The Au NPs were confirmed to extensively broaden the absorption spectrum of TiO into the visible range and to reduce the onset potential of these photoelectrodes. Most importantly, TiO@rGO@Au hybrid exhibited a 14-fold enhanced PEC efficiency under visible light and a 2.5-fold enrichment in the applied bias photon-to-current efficiency at much lower bias potential compared with pristine TiO. Incident photon-to-electron conversion efficiency measurements highlighted a synergetic effect between Au plasmon sensitization and rGO-mediated facile charge separation/transportation, which is believed to significantly enhance the PEC activity of these nanostructures under simulated and visible light irradiation. Under the selected operating conditions the incorporation of Au NPs and rGO into TiO resulted in a remarkable boost in the H evolution rate (17.8 μmol/cm) compared to a pristine TiO photoelectrode reference (7.6 μmol/cm). In line with these results and by showing excellent stability as a photoelectrode, these materials are herin underlined to be of promising interest in the PEC water splitting reaction.

Comprehensive insight into the thermochemical, photochemical and electrochemical reduction of CO2 to methane and long-chain hydrocarbons as alternative fuels.

Hierarchically organized porous carbonized‐Co3O4 inverse opal nanostructures (C‐Co3O4 IO) are synthesized via complementary colloid and block copolymer self‐assembly, where the triblock copolymer Pluronic P123 acts as the template and the carbon source. These highly ordered porous inverse opal nanostructures with high surface area display synergistic properties of high energy density and promising bifunctional electrocatalytic activity toward both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). It is found that the as‐made C‐Co3O4 IO/Ketjen Black (KB) composite exhibits remarkably enhanced electrochemical performance, such as increased specific capacity (increase from 3591 to 6959 mA h g−1), lower charge overpotential (by 284.4 mV), lower discharge overpotential (by 19.0 mV), and enhanced cyclability (about nine times higher than KB in charge cyclability) in Li–O2 battery. An overall agreement is found with both C‐Co3O4 IO/KB and Co3O4 IO/KB in ORR and OER half‐cell tests using a rotating disk electrode. This enhanced catalytic performance is attributed to the porous structure with highly dispersed carbon moiety intact with the host Co3O4 catalyst.

Solar energy conversion has emerged as an attractive pathway in the decomposition of hazardous organic pollutants. Herein, tridoped β-NaYF 4 :Yb 3+ ,Tm 3+ ,Gd 3+ upconversion (UC) nanorods were embedded in a carbon-doped mesostructured TiO 2 hybrid film using triblock copolymer P123 acting as a mesoporous template and carbon source. The photoactivity of our novel material was reflected in the degradation of nitrobenzene, as a representative organic waste. The broad-band absorption of our rationally designed UC nanorod-embedded C-doped TiO 2 in the UV to NIR range unveiled a remarkable increase in nitrobenzene degradation (83%) within 3 h compared with pristine TiO 2 (50%) upon light irradiation. These results establish for the first time a synergetic bridge between the effects of a creative photon trapping TiO 2 architecture, improved NIR light-harvesting efficiency upon UC nanorod incorporation, and a simultaneous decrease in the band gap energy and increased visible light absorption by C-doping of the oxide lattice. The resulting nanostructure was believed to favor efficient charge and energy transfer between the photocatalyst components and to reduce charge recombination. Our novel hybrid nanostructure and its underlined synthesis strategy reflect a promising route to improve solar energy utilization in environmental remediation and in a wide range of photocatalytic applications, e.g., water splitting, CO 2 reutilization, and production of fuels.

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Harvesting low-energy photons by strategically exploiting the photocatalytic properties of plasmonic and upconversion nanocomponents is a promising route to improve solar energy utilization. Herein, a rationally designed 3D composite photoanode integrating NIR-responsive upconversion nanocrystals (UCNs) and visible-responsive plasmonic Au nanoparticles (NPs) into 3D TiO2 inverse opal nanostructures (Au/UCN/TiO2) has been shown to extend the solar energy utilization in the UV–vis–NIR range. The NIR-responsive properties of NaYF4:Yb3+-based UCNs doped with Er3+ or Tm3+ ions, and the effect of an alternating sequential introduction of UCN and Au, have been assessed. With an extended overlap between the emission of Er-UCN and the characteristic SPR band of Au, our ternary Au/Er-UCN/TiO2 hybrid nanostructure unveiled a notable 10-fold improvement in photocurrent density under UV–vis–NIR illumination compared with a pristine TiO2 reference. The Au incorporation was confirmed to play a key role in enhancing the efficiency of light harvesting and to synergistically facilitate the energy transfer from UCNs to TiO2. This work further dissected plausible mechanistic pathways combining collected photoelectrocatalytic results, with electrochemical impedance measurements and transient absorption spectroscopic measurements. The synthesis and catalytic performance of our Au/UCN/TiO2 and the underlying mechanism here proposed are expected to reflect extended applicability in analogous applications for efficient solar-to-energy sustainable platforms.

Critical challenges of Li–S batteries are related with the instability of Li metal during cycling. To overcome these issues, electrolyte modification and artificial SEI layer incorporation-based strategies have been here reviewed.

In recent years, a promising role of plasmonic metal nanoparticles (NPs) has been demonstrated toward an improvement of the catalytic efficiency of well‐designed hybrid electrocatalysts. In particular, the coupling of plasmonic functionality with the metal‐based core–shell architectures in plasmon‐enhanced electrocatalysis provides a sustainable route to improve the catalytic performances of the catalysts. Herein, the rationally designed AuNPs wrapped with reduced graphene oxide (rGO) spacer along with PdNPs (AuNP@rGO@Pd) as the final composite are reported. The rGO is proposed to promote the reduction of PdO, greatly enhance the conductivity, and catalytic activity of these nanohybrid structures. The plasmon‐enhanced electrocatalytic performance of optimized AuNP@rGO(1)@Pd exhibits an ≈1.9‐ and 1.1‐fold enhanced activity for the hydrogen evolution reaction and oxygen evolution reaction, respectively. The final composite also exhibits a superior stability up to 10000 s compared with the commercial Pd/C. The mechanism of the enhanced catalytic performance is monitored through in situ X‐ray absorption spectroscopy by observing the generated electron density under light irradiation. The results demonstrate that the energetic charge carriers are concentrated in the incorporated PdNPs, allowing higher catalytic performances for the overall water‐splitting reaction. The conclusions herein drawn are expected to shed light on upcoming plasmon‐induced electrocatalytic studies with analogous hybrid nanoarchitectures.