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CdS-based 3D nano/micro-architectures, their formation mechanism and tailoring of properties for visible light induced photocatalytic activities in energy and environmental applications are presented.

Graphene and its derivatives are used as metal-free photocatalysts because of their fascinating optoelectronic properties which can further be improved by chemical doping for advanced functional applications in the field of energy and environment.

Developing highly efficient electrocatalysts to facilitate the sluggish cathodic oxygen reduction reaction (ORR) is a key challenge for high-performance fuel cells. Low-dimensional materials have attracted great attention recently because of their unique structure and properties. In this review, the application of zero-dimensional (0D), one‐dimensional (1D), and two‐dimensional (2D) materials in ORR are discussed and particular attention is given to the relationship between their structure and the ORR activity. Graphene-based materials, transition metal dichalcogenides, transition metal oxide, nanotubes, nanoribbons, nanowires, and single-atom ORR catalysts are introduced and classified by their geometric dimension.

Lithium-sulfur (Li–S) and sodium-sulfur (Na–S) batteries are the promising energy storage systems of next-generation because of their high theoretical specific energy, abundant storage of sulfur, and long cycle life. However, both of them are suffering the low conductivity, volume expansion of cathode, corrosion of Li/Na anode by the electrolyte, shuttle effect of polysulfides, and dendrites formation of Li/Na metal anode. The new technology of atomic layer deposition (ALD) has shown great potential in Li-ion and Na-ion batteries due to the outstanding conformal deposition, digitized and accurate film thickness, and the mild low-temperature growth on complex substrates, such as mesoporous materials. Inspired by these benefits, recently, more and more studies successfully employed ALD strategy to fabricate or modify cathodes, anodes, interlayers, and all-solid-state electrolytes with precisely atomic level conformal films to improve their conductivity, stability, and mechanical properties for the high electrochemical performance of Li–S and Na–S batteries. To our knowledge, this is the first review to systematically summarize the most recent advances of ALD for both Li–S and Na–S batteries applications. Especially, various functions of the ALD technique in Li–S and Na–S batteries have been presented and fully discussed with classical examples. Further, the mechanism, advantages, and future development of ALD are also proposed and discussed.

Exploring highly active and stable bifunctional water-splitting electrocatalysts at ultra-high current densities is remarkably desirable. Herein, 3D nickel-iron phosphides nanosheets modified by MnO

Graphene, one of the most promising two-dimensional (2D) nanomaterials, has gained substantial attention in several areas of materials science. Due to its unique mechanical, electrical, optical, an...

The electromagnetic radiation of household appliances and radioactivity of stone materials from residences were determined using integrated magnetometer and γ-ray spectrometer techniques. The radiation levels of desktop computers were greater than that of notebook computers, while microwave ovens and induction cookers produced low-frequency electromagnetic fields during the operation. The safety distances for hair drier, desk lamp, and patch board were ca. 50 cm, whereas those of the rest appliances were ca. 30 cm. Radioactive tests of stones collected from certain regions were conducted. The specific activities of 226Ra, 232Th, and 40K were used to calculate internal exposure indexes (I Ra) and external exposure indexes (I γ). Moreover, both the I Ra and I γ for wall coatings were putty < tile adhesive, thereby the I Ra and I γ for bathroom furniture were ceramic facet < pottery basin < flush toilet. Natural radionuclides widely exist in interior decorations, indicating that humans in open radioactive environments receive background radiation all the time.

Colloidal semiconductor quantum dots (QDs) are considered as promising building blocks to fabricate efficient and stable optoelectronic devices, thanks to their size/shape/composition-dependent electronic and optical properties based on the quantum confinement effect. However, inadequate light absorption and undesirable charge recombination events still limit the efficiency and long-term stability of solar energy to fuel conversion in QD-based photoelectrochemical (PEC) cells. In this work, we engineer the optoelectronic properties and band alignment in colloidal heterostructured CdS/CdSe core/shell QDs by tuning the shell thickness. Starting with a 3.0 nm CdS QD core (in diameter), we investigate the changes in structural and optical properties as a function of CdSe shell thickness (0.6–1.9 nm). We show that the optimization of the shell thickness can significantly broaden the light absorption range towards longer wavelengths and enhance the rate of photoelectron separation and transport in photoanodes made of QDs sensitized TiO2 mesoporous film. Complemented by theoretical modeling, we find that the band alignment in this heterostructured system can be engineered from quasi type-II (electrons are localized over the entire QDs but holes are mostly delocalized in shell) to inverted type-I (both electrons and holes are largely delocalized in shell) by changing the shell thickness. As a proof-of-concept, employing QDs with optimal shell thickness of 1.6 nm together with carbon nanotube doped TiO2 as photoanode in PEC cells, we obtained a very high photocurrent density of ~ 16.0 mA/cm2 (at 0.9 V vs. the reversible hydrogen electrode, RHE), which is the highest value ever reported for PEC cells based on CdS/CdSe QDs. We also observed an excellent long-term stability (maintaining 83% of its initial value after four hours) under one sun illumination (AM 1.5G, 100 mW/cm2). These results indicate that optimizing the design and band engineering of heterostructured core/shell QDs is a facile and efficient approach to enhance the performance of QDs-based PEC cells and other optoelectronic devices.

CO

Electrochemical CO2 reduction reaction (ECO2RR) offers an opportunity to sustainably convert CO2 into value-added fuels and chemicals by using the electricity that could be generated by renewable energies. Recently, enormous efforts are focused on the development of metal-based catalysts for the selective ECO2RR with high efficiency. Multi-metallic catalyst design emerges as one of the most promising strategies for the promotion of the Faradaic efficiency (FE), the current density, and the lowering of the overpotential of the catalysts for ECO2RR. The synergistic effects of the different metal sites in the hybrid catalysts are of significance for the enhancement of the ECO2RR performance. This review summarizes the rational design of multi-metallic catalysts, including alloy, atomically dispersed multi-metallic sites, and others, along with the popular metal elements studied in multi-metallic catalysts to clarify the advantages of different metal elements for ECO2RR. The density functional theory (DFT) simulations and advanced in-situ characterizations that contribute to demystifying the synergies between metal elements are highlighted. Challenges and outlook concerning the catalyst design and reaction mechanism of multi-metallic catalysts for ECO2RR are also discussed.

The development of high efficient and inexpensive photocatalyst for oxidation of indoor gaseous benzene is a big challenge. In this paper, a simple compound containing only one metal element named antimony oxide hydrate (Sb 2 O 5 ·3H 2 O) is prepared by a facile hydrolysis–oxidation method. The photocatalytic activity for oxidation of benzene over Sb 2 O 5 ·3H 2 O is investigated for the first time. The conversion ratio and mineralization of benzene are 35.0% and 55% over Sb 2 O 5 ·3H 2 O, which are 3.5 and 5.5 times higher than that of P25. Reactive oxygen species, including O 2 − and OH, are detected by ESR experiments. The large amount of O 2 − and long lived OH over antimony oxide hydrate is the main reason for its good photocatalytic activity, and it is also proved that both O 2 − and OH are mainly origin from oxygen reduction. We believe that this energy saving, inexpensive and high efficient photocatalyst has potential industrial application value.

Photonic crystals with highly ordered structure have presented a prospective application in the design of photocatalysts. Herein, we fabricated visible-light active β-Bi2O3 photonic crystals via a modified sandwich infiltration method. By using the acetylacetone-complexed metal ion precursors, pure β-Bi2O3 photonic crystals with highly ordered structure could be obtained at a calcination temperature of 400 °C. Benefited from the facilitated mass transport in the highly ordered structure, β-Bi2O3 photonic crystals exhibited higher photocatalytic activity towards organic pollutions degradation than porous β-Bi2O3 and β-Bi2O3 nanocrystals. Furthermore, the photonic band gap of β-Bi2O3 photonic crystals could be modulated to overlap its electronic band gap by changing the macropore diameter into 220 nm. Slow photon effect could be observed over the β-Bi2O3 photonic crystals with a pore diameter of 220 nm, which enhanced the electronic band gap absorption and further improved the corresponding photocatalytic activity. The enhanced activity stability of β-Bi2O3 photonic crystals could also be observed. Based on the detection of active species, the degradation mechanism over β-Bi2O3 photonic crystals was discussed. The fabrication of β-Bi2O3 photonic crystals in this study provides experimental guidance for developing photonic crystals with enhanced visible light absorption and photocatalytic activities.

In the photocatalytic oxidation of benzene over BiVO4/TiO2, some deactivation was observed at 30 °C, while stable activity was maintained at higher temperatures. To further take advantage of the heating effect during photocatalysis, Pt was loaded onto the BiVO4/TiO2 sample, owing to its excellent performance in thermocatalysis. The results show that the Pt/BiVO4/TiO2 sample with a Pt loading amount of 1.0 wt% has the best activity in the oxidation of benzene, compared with others containing loading amounts of 0.2, 0.5 and 2.0 wt%. Benzene can be totally oxidized at 80 °C with an obvious photothermocatalytic synergetic effect, whose mechanism is discussed and summarized as three main paths. In this case, the heating effect of infrared light from a light source can be helpful in photocatalysis, which is an inspiration for increasing the availability of solar energy.

CO2 reduction reaction (CO2 RR) provides a promising strategy for sustainable carbon fixation by converting CO2 into value-added fuels and chemicals. In recent years, considerable efforts are focused on the development of transition-metal (TM)-based catalysts for the selectively electrochemical CO2 reduction reaction (ECO2 RR). Co-based catalysts emerge as one of the most promising electrocatalysts with high Faradaic efficiency, current density, and low overpotential, exhibiting excellent catalytic performance toward ECO2 RR for CO and HCOOH productions that are economically viable. The intrinsic contribution of Co and the synergistic effects in Co-hybrid catalysts play essential roles for future commercial productions by ECO2 RR. This review summarizes the rational design of Co-based catalysts for ECO2 RR, including molecular, single-metal-site, and oxide-derived catalysts, along with the nanostructure engineering techniques to highlight the distribution of the ECO2 RR products by Co-based catalysts. The density functional theory (DFT) simulations and advanced in situ characterizations contribute to interpreting the synergies between Co and other materials for the enhanced product selectivity and catalytic activity. Challenges and outlook concerning the catalyst design and reaction mechanism, including the upgrading of reaction systems of Co-based catalysts for ECO2 RR, are also discussed.