Solar water splitting, which has been a topic of intensive research interest for several decades, is one of the promising approaches to utilize renewable energy to maintain the sustainable prosperity ...of our society. However, until now no mature photoelectrochemical cell has been used in practical large-scale applications because of the difficulties to satisfy all the harsh requirements, including high energy conversion efficiency, high stability and low cost. This feature article reviews the recent progress in developing photocathodes for photoelectrochemical cells for solar hydrogen production. Both the development of the p-type semiconductor light absorbers and the efforts to develop synergistic approaches to improve the overall performance of the photocathode are discussed.
Recent efforts to improve the performance of photocathodes for hydrogen evolution are reviewed.
Organometal trihalide perovskite-based light absorbers have attracted great attention due to their excellent photovoltaic properties. The swift developments in the device fabrication techniques have ...led to the power conversion efficiencies exceeding 17%. In this minireview, we will present the typical characteristics of the materials and device structures, followed by analysing updated understandings on the operational principles of the devices. We will also point out the outstanding issues regarding the materials and devices. Finally, as a high-efficiency newcomer to the solar cell family, the potential impact on the relevant photovoltaics will be discussed.
This minireview comments on the development and potential impact of perovskite solar cells on the solar cell family.
This communication describes the use of Ag sub(2)S-encapsulated Au nanorods (AuNRatAg sub(2)S) to enhance longer wavelength sunlight utility in dye-sensitized solar cells (DSSCs). We observed that ...the longitudinal plasmon resonance of AuNRs induces a remarkable increase of 37.6% in photocurrent generation at 600-720 nm. Optical characterizations indicate that the increased optical density and decreased light transmission as a result of AuNRs incorporation engender the striking improvement. With AuNRatAg sub(2)S, the final power conversion efficiency (PCE) of the DSSC with a thin anode (6 mu m) increases from 4.3% to 5.6%, which is comparable to that of a pure TiO sub(2) anode based DSSC (5.8%) with a film thickness of 11 mu m. Further, incorporation of AuNRatAg sub(2)S into the thick anode leads to the PCE increasing to 7.1%.
Ternary organic solar cells are emerging as a promising strategy to enhance device power conversion efficiency by broadening the range of light absorption via the incorporation of additional ...light-absorbing components. However, how to find compatible materials that allow comparable loadings of each component remains a challenge. In this article, we focus on studying the donor polymer compatibilities in ternary systems from a morphological point of view. Four typical donor polymers with different chemical structures and absorption ranges were mutually combined to form six distinct ternary systems with fullerene derivative acceptors. Two compatible ternary systems were identified as showing significant improvements of efficiency from both binary control devices. Ternary morphologies were characterized by grazing incident X-ray scattering and correlated with device performance. We find that polymers that have strong lamellar interactions and relatively similar phase separation behaviors with the fullerene derivative are more likely to be compatible in ternary systems. This result provides guidance for polymer selection for future ternary organic solar cell research while relaxing the limitation of chemical structure similarity and greatly extends the donor candidate pool.
An S‐mandelic acid imprinted chitosan resin was synthesized by cross‐linking chitosan with glutaraldehyde in 2% acetic acid solution. S‐Mandelic acid imprinted chitosan resin was used to ...enantioselectively separate racemic mandelic acid in aqueous medium. When keeping the pH of sample solution (100 mM Tris‐H3PO4) at 3.5 and adsorption time at 40 min, the enantiomer excess of mandelic acid in supernatant was 78.8%. The adsorption capacities of S‐mandelic acid imprinted chitosan resin for S‐ and R‐mandelic acid were determined to be 29.5 and 2.03 mg/g, respectively. While the adsorption capacities of non‐imprinted cross‐linked chitosan for S‐ and R‐mandelic acid were 2.10 and 2.08 mg/g, respectively. The result suggests that the imprinted caves in S‐mandelic acid imprinted chitosan resin are highly matched with S‐mandelic acid molecule in space structure and spatial arrangement of action sites. Interestingly, the enantiomer excess value of mandelic acid in supernatant after adsorption of racemic mandelic acid by R‐mandelic acid imprinted cross‐linked chitosan was 25.4%. The higher enantiomer excess value by S‐mandelic acid imprinted chitosan resin suggests that the chiral carbons in chitosan and the imprinted caves in S‐mandelic acid imprinted chitosan resin combine to play roles for the enantioselectivity of S‐mandelic acid imprinted chitosan resin toward S‐mandelic acid. Furthermore, the excellent enantioselectivity of S‐mandelic acid imprinted chitosan resin toward S‐mandelic acid demonstrates that using chiral chitosan as functional monomer to prepare molecularly imprinted polymers has great potential in enantioseparation of chiral pharmaceuticals.
The past two years have witnessed unprecedentedly rapid development of organic-inorganic halide perovskite-based solar cells. The solution-processability and high efficiency make this technology ...extraordinarily attractive. The intensive investigations have accumulated rich experiences in the perovskite fabrication; while the mechanism of the chemical synthesis still remains unresolved. Here, we set up the chemical equation of the synthesis and elucidate the reactions from both thermodynamic and kinetic perspectives. Our study shows that gaseous products thermodynamically favour the reaction, while the activation energy and "collision" probability synergistically determine the reaction rate. These understandings enable us to finely tune the crystal size for high-quality perovskite film, leading to a record fill factor among similar device structures in the literature. This investigation provides a general strategy to explore the mechanism of perovskite synthesis and benefits the fabrication of high-efficiency perovskite photoactive layer.
The formation of chemical bonds between metal ions and their supports is an effective strategy to achieve good catalytic activity. However, both the synthesis of active metal species on a support and ...control of their coordination environment are still challenging. Here, we show the use of an organic compound to produce tubular carbon nitride (TCN) as a support for Pd nanoparticles (NPs), creating a composite material (NP-Pd-TCN). It was found that Pd ions preferentially bind with the electron-rich N atoms of TCN, leading to strong metal-support interactions that benefit charge transfer from g-C
3
N
4
to Pd. X-ray absorption spectroscopy further revealed that the metal-support interactions resulted in the formation of Pd-N bonds, which are responsible for the improvement in the charge dynamics as evidenced by the results from various techniques including photoluminescence (PL) spectroscopy, photocurrent measurements, and electrochemical impedance spectroscopy (EIS). Owing to the good dynamical properties, NP-Pd-TCN was used for photocatalytic hydrogen evolution under visible-light irradiation (
λ
> 420 nm) and an excellent evolution rate of ∼ 381 µmol·h
−1
(0.02 g of the photocatalyst) was attained. This work aims to promote a strategy to synthesize efficient photocatalysts for hydrogen production by controllably introducing metal nanoparticles on a support and in the meantime forming chemical bonds to achieve intimate metal-support contact.
Fenton or photocatalytic degradations of organic contaminants are recognized as promising approaches to address the increasing environmental pollution issues. Herein, we develop the effective ...synergistic catalysis reaction of Fenton and photocatalysis based on a loofah sponge-like Fe
2
O
x
/C nanocomposite, which exhibits excellent nitrobenzene photocatalytic degradation property. It is noted that Fe
2
O
3
nanoparticles with surface Fe
2+
species were encapsulated with an ultrathin carbon layer (denoted as Fe
2
O
x
/C) via a supramolecular self-sacrificing template and following thermal treatment process. The experimental results indicated that the thin layer carbon coating not only inhibited the Fe iron leaching from the Fe
2
O
x
but also prompted the separation and transferring of electrons-hole pairs. The introduction of Fe
2
O
x
/C enables the Fenton reaction to induce a rapid Fe
2+
/Fe
3+
cycle, and meanwhile, together with the photocatalytic reaction to produce continuous active substances for the subsequent degradation catalytic reaction without successive H
2
O
2
, resulting in the inexpensive and the effective photocatalytic procedure. As a result, 100% nitrobenzene (100 mg/L) was degraded and 97% of the organic carbon was mineralized in 90 min using the Fe
2
O
x
/C (0.1 g/L) at a low H
2
O
2
dosage (0.50 mM), under air mass (AM) 1.5 irradiation. Theoretical calculations confirmed that the Fe
2
O
x
/C-600 with thin carbon layer promoted the dissociation of H
2
O
2
and the ·OH desorption. The synergistic catalysis of this work may provide new ideas for low-cost and more efficient treatment of pollutants.
The advent of graphene opens up the research into two-dimensional (2D) materials, which are considered revolutionary materials. Due to its unique geometric structure, graphene exhibits a series of ...exotic physical and chemical properties. In addition, single-element-based 2D materials (Xenes) have garnered tremendous interest. At present, 16 kinds of Xenes (silicene, borophene, germanene, phosphorene, tellurene, etc.) have been explored, mainly distributed in the third, fourth, fifth, and sixth main groups. The current methods to prepare monolayers or few-layer 2D materials include epitaxy growth, mechanical exfoliation, and liquid phase exfoliation. Although two Xenes (aluminene and indiene) have not been synthesized due to the limitations of synthetic methods and the stability of Xenes, other Xenes have been successfully created via elaborate artificial design and synthesis. Focusing on elemental 2D materials, this review mainly summarizes the recently reported work about tuning the electronic, optical, mechanical, and chemical properties of Xenes via surface modifications, achieved using controllable approaches (doping, adsorption, strain, intercalation, phase transition, etc.) to broaden their applications in various fields, including spintronics, electronics, optoelectronics, superconducting, photovoltaics, sensors, catalysis, and biomedicines. These advances in the surface modification of Xenes have laid a theoretical and experimental foundation for the development of 2D materials and their practical applications in diverse fields.
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