Realization of the Zn3+ oxidation state

Suppressing Redox Reactions at the Perovskite-Nickel Oxide Interface with Zinc Nitride to Improve the Performance of Perovskite Solar Cells

For p-i-n perovskite solar cells (PSCs), nickel oxide (NiOx) hole transport layers (HTLs) are the preferred interfacial layer due to their low cost, high mobility, high transmittance, and stability. However, the redox reaction between the Ni≥3+ and hydroxyl groups in the NiOx and perovskite layer leads to oxidized CH3NH3 + and reacts with PbI in the perovskite, resulting in a large number of non-radiative recombination sites. Among various transition metals, an ultra-thin zinc nitride (Zn3N2) layer on the NiOx surface is chosen to prevent these redox reactions and interfacial issues using a simple solution process at low temperatures. The redox reaction and non-radiative recombination at the interface of the perovskite and NiOx reduce chemically by using interface modifier Zn3N2 to reduce hydroxyl group and defects on the surface of NiOx. A thin layer of Zn3N2 at the NiOx/perovskite interface results in a high Ni3+/Ni2+ ratio and a significant work function (WF), which inhibits the redox reaction and provides a highly aligned energy level with perovskite crystal and rigorous trap-passivation ability. Consequently, Zn3N2-modified NiOx-based PSCs achieve a champion PCE of 21.61%, over the NiOx-based PSCs. After Zn3N2 modification, the PSC can improve stability under several conditions.

Selective and Scalable CO2 Electrolysis Enabled by Conductive Zinc Ion-Implanted Zeolite-Supported Cadmium Oxide Nanoclusters

Catalyst supports play an essential role in catalytic reactions, hinting at pronounced metal-support effects. Zeolites are a propitious support in heterogeneous catalysts, while their use in the electrocatalytic CO2 reduction reaction has been limited as yet because of their electrically insulating nature and serious competing hydrogen evolution reaction (HER). Enlightened by theoretical prediction, herein, we implant zinc ions into the structural skeleton of a zeolite Y to strategically tailor a favorable electrocatalytic platform with remarkably enhanced electronic conduction and strong HER inhibition capability, which incorporates ultrafine cadmium oxide nanoclusters as guest species into the supercages of the tailored 12-ring window framework. The metal d-bandwidth tuning of cadmium by skeletal zinc steers the extent of substrate-molecule orbital mixing, enhancing the stabilization of the key intermediate *COOH while weakening the CO poisoning effect. Furthermore, the strong cadmium-zinc interplay causes a considerable thermodynamic barrier for water dissociation in the conversion of H+ to *H, potently suppressing the competing HER. Therefore, we achieve an industrial-level partial current density of 335 mA cm-2 and remarkable Faradaic efficiency of 97.1% for CO production and stably maintain Faradaic efficiency above 90% at the industrially relevant current density for over 120 h. This work provides a proof of concept of tailored conductive zeolite as a favorable electrocatalytic support for industrial-level CO2 electrolysis and will significantly enhance the adaptability of conductive zeolite-based electrocatalysts in a variety of electrocatalysis and energy conversion applications.

Density Functional Theory Study of Low-Dimensional (2D, 1D, 0D) Boron Nitride Nanomaterials Catalyzing Acetylene Acetate Reaction

In this paper, density functional theory (DFT) was used to study the possibility of low-dimensional (2D, 1D, 0D) boron nitride nanomaterials to catalyze acetylene acetate reaction, and further explore the possible source of this catalytic activity. It is found that the catalytic activity of boron nitride nanomaterials for acetylene acetate reaction will change with the change of the geometric structure (dimension) and reaction site of the catalyst. From the geometric structure, the reaction components and the zero-dimensional BN catalyst can form chemical bonds and form complexes, while only physical adsorption occurs on the surface of the one-dimensional and two-dimensional BN catalysts. From the reaction site, the properties of different C sites on the B₁₂N₁₂NC-C₂H₂ complexes are different. Namely, a C atom connected with a B atom is more likely to have an electrophilic reaction with H⁺, and a C atom connected with an N atom is more likely to have a nucleophilic reaction with CH₃COO⁻. Through the study of three kinds of BN nanomaterials with low dimensions, we found that the zero-dimensional B₁₂N₁₂ nanocage broke the inherent reaction inertia of BN materials and showed good catalytic activity in an acetylene acetate reaction, which is very likely to be a non-metallic catalyst for the acetylene gas-phase preparation of vinyl acetate.

Reply to the 'Comment on "Realization of the Zn3+ oxidation state"' by Y. Shang, N. Shu, Z. Zhang, P. Yang and J. Xu, Nanoscale, 2022, , DOI: 10.1039/D1NR07031B

In a recent paper (https://doi.org/10.1039/D1NR02816B), we suggested that Zn can assume a +3-oxidation state when interacting with super-electrophilic clusters, BeB₁₁(CN)₁₂ and BeB₂₃(CN)₂₂. In a comment to our paper (https://doi.org/10.1039/D1NR07031B), Shang et al. have questioned this suggestion. Using density functional theory with the TPSSh functional and def2-SVP basis sets in the Gaussian16 software and semiempirical localized orbital bonding analysis (LOBA), the authors have made three major claims: (1) the oxidation state of Zn in Zn[BeB₁₁(CN)₁₂] and Zn[BeB₂₃(CN)₂₂] is +2; (2) electron affinities are not reliable to probe the oxidation states; and (3) our results are "misleading" because these are based on the VASP code. According to these authors, VASP is not suitable for small clusters because it uses projected augmented wave (PAW) pseudopotentials. In the following, we show that these claims are invalid, caused by both misunderstanding and the authors' use of a lower-level theory.

Comment on "Realization of the Zn3+ oxidation state" by H. Fang, H. Banjade, Deepika and P. Jena, Nanoscale, 2021, , 14041-14048

Two zinc-boron clusters (ZnBeB₁₁(CN)₁₂ and ZnBeB₂₃(CN)₂₂) reported in a theoretical study by P. Jena and co-workers are reinvestigated using quantum chemistry calculations. The results prove that the zinc atoms in these two clusters retain a normal oxidation state of +2, overturning the conclusion reached in the previous study that a +3 oxidation state is present. The semi-empirical LOBA method points out this contrast, which is demonstrated via various wavefunction analysis approaches. No unpaired electrons are observed on zinc atoms nor is there a spin density difference distribution, revealing that the zinc atoms have a fully occupied 3d¹⁰ electron shell. Density of states studies give the same conclusion, and they further show that zinc atoms adopt an sp²-hybrid type during bonding. From the perspective of energy, we advise that the electron affinity energy is not a reliable way of evaluating the oxidation state. Instead, binding energy calculations and constrained DFT are applicable, and these also support the presence of Zn²⁺. The simulated XPS peaks are consistent with the experimental data for Zn(II) measured in ZnS. Lastly, the ETS-NOCV method is adopted to give insights into the bonding structures between zinc atoms and boron clusters. It is suggested that future theoretical research into similar problems is analyzed more cautiously to avoid potentially misleading other researchers.