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Rare-earth ion-doped semiconducting phosphor has attracted extensive attention due to the ability to achieve efficient luminescence through the host sensitization. Here, we present a new type red-emitting Eu3+ -doped BiOCl phosphors possessing a broad excitation band in the near-ultraviolet ( NUV) region. Experimental measurements and theoretical calculations confirm that Eu3+ ion dopants result in forming impurity energy level near valence band, and the excellent broadband NUV-exciting ability of Eu3+ ion is due to the electronic transitions of BiOCl band gap. Moreover, the highest emission intensity of the phosphors is from the 5D0 → 7F4 transition of Eu3+ around 699 nm (far-red) through whether host excitation or direct Eu3+ ions excitation, which lie in the particular structure of BiOCl crystals. Our results indicate that the Eu3+ -doped BiOCl crystals show great potential as red phosphors for white-light-emitting diodes. [ABSTRACT FROM AUTHOR]

Abstract: As promising light-absorber material for solar cells, Cu2ZnSnS4 was found to have another crystal structure (wurtzite-kesterite) in addition to the conventional zinc blende-kesterite structure. Structural flexibility of Cu2ZnSnS4 opens up an avenue to develop light-absorber material with novel exciting properties and applications. However, its electronic and optical properties have not been comprehensively studied yet. For this purpose, the method of density functional theory within hybrid functional of PBE0 was adopted to study the structural, electronic, and optical properties of wurtzite-kesterite Cu2ZnSnS4 in this Letter. The calculated results suggested that the energy of its band gap is about 1.372 eV and it has obvious optical anisotropy. Furthermore, its crystal structure leads local internal fields that are especially beneficial to suppress the recombination of photoexcited electron–hole pairs. [Copyright &y& Elsevier]

Abstract: The behavior of water molecule on anatase TiO2 (101) surface has been investigated by density functional theory calculations. The primary purpose of this Letter is to clarify the distinctions between molecular adsorption and dissociative adsorption of water on anatase TiO2 (101) surface. By analyzing interaction potential forms and bonding mechanism, it is found that the dipole interaction is the crucial factor for water adsorption on anatase TiO2 (101) surface. The adiabatic potential energy surface calculations indicate that the on-surface diffusion of water molecule is anisotropy: its diffusion energy barrier along [010] direction is smaller than that of along direction. [Copyright &y& Elsevier]

Electrochemical nitrate reduction reaction (NO 3 RR) is a promising approach to realize ammonia generation and wastewater treatment. However, the transformation from NO 3 - to NH 3 involves multiple proton-coupled electron transfer processes and by-products (NO 2 - , H 2 , etc.), making high ammonia selectivity a challenge. Herein, a two-phase nanoflower P-Cu/Co(OH) 2 electrocatalyst consisting of P-Cu clusters and P-Co(OH) 2 nanosheets is designed to match the two-step tandem process (NO 3 - to NO 2 - and NO 2 - to NH 3 ) more compatible, avoiding excessive NO 2 - accumulation and optimizing the whole tandem reaction. Focusing on the initial 2e - process, the inhibited * NO 2 desorption on Cu sites in P-Cu gives rise to the more appropriate NO 2 - released in electrolyte. Subsequently, P-Co(OH) 2 exhibits a superior capacity for trapping and transforming the desorbed NO 2 - during the latter 6e - process due to the thermodynamic advantage and contributions of active hydrogen. In 1 m KOH + 0.1 m NO 3 - , P-Cu/Co(OH) 2 leads to superior NH 3 yield rate of 42.63 mg h - 1  cm - 2 and NH 3 Faradaic efficiency of 97.04% at -0.4 V versus the reversible hydrogen electrode. Such a well-matched two-step process achieves remarkable NH 3 synthesis performance from the perspective of optimizing the tandem catalytic reaction, offering a novel guideline for the design of NO 3 RR electrocatalysts., (© 2024 Wiley‐VCH GmbH.)

Photocatalytic water splitting for clean hydrogen production has been a very attractive research field for decades. However, the insightful understanding of the actual active sites and their impact on catalytic performance is still ambiguous. Herein, a Pr-doped TiO 2 -supported Cu single atom (SA) photocatalyst is successfully synthesized (noted as Cu/Pr-TiO 2 ). It is found that Pr dopants passivate the formation of oxygen vacancies, promoting the density of photogenerated electrons on the CuSAs, and optimizing the electronic structure and H * adsorption behavior on the CuSA active sites. The photocatalytic hydrogen evolution rate of the obtained Cu/Pr-TiO 2 catalyst reaches 32.88 mmol g -1  h -1 , 2.3 times higher than the Cu/TiO 2 . Innovatively, the excellent catalytic activity and performance is attributed to the active sites change from O atoms to CuSAs after Pr doping is found. This work provides new insight for understanding the accurate roles of single atoms in photocatalytic water splitting., (© 2024 Wiley‐VCH GmbH.)

In this work, we used Cu-BTC-IPA and Co(NO 3 ) 2 ·6H 2 O as precursors to synthesize CuCoO 2 (CCO) nanocrystals with a suitable crystal phase, morphology and high yield by changing the process parameters, such as reactant concentration, reactant ratio, mineralizer dosage, and the type of polyvinylpyrrolidone surfactant. In addition, the effects of different concentrations (1 at%, 3 at%, 5 at%) of Fe doping on the crystal structure and oxygen evolution reaction (OER) performance of CCO were studied. The experimental results show that Fe ions are uniformly doped into the lattice to replace the A-site (Cu + ) position, which not only reduces the grain size of CCO, but also increases its specific surface area. We further employed the density functional theory (DFT) method to simulate the OER process of transition metal Fe-doped CCO (A-site substitution) and proposed that Fe doping can reduce the Gibbs free energy of each step and promote the formation of each intermediate, thereby improving its OER catalytic performance. In 1.0 M KOH electrolyte, the 3 at% Fe-doped CCO (Ni@3FCCO) electrode has the best OER performance ( η 10 = 369 mV, Tafel slope = 69 mV dec -1 ), and the required overpotential to attain 10 mA cm -2 slightly increased (∼30.2 mV) after 18 hours of continuous OER. The crystal morphology and chemical composition did not change significantly before and after the long-term OER test, indicating that the 3FCCO nanosheets have good OER activity and stability. We have proposed two reasons for the significant improvement of OER performance for Fe-doped CCO nanosheets: (1) the partial substitution of Cu cations by Fe cations not only regulates the electronic structure of CCO, making the catalytically active center no longer a single Co site, but also contains the Fe site, thus increasing the number of overall active sites; (2) the synergistic effect between Fe cations and Co cations in the OER process could enhance the activity of a single active site.