Structure of Amorphous Selenium: Small Ring, Big Controversy.

Selenium (Se) discovered in 1817 belongs to the family of chalcogens. Surprisingly, despite the long history of over two centuries and the chemical simplicity of Se, the structure of amorphous Se (a-Se) remains controversial to date regarding the dominance of chains versus rings. Here, we find that vapor-deposited a-Se is composed of disordered rings rather than chains in melt-quenched a-Se. We further reveal that the main origin of this controversy is the facile transition of rings to chains arising from the inherent instability of rings. This transition can be inadvertently triggered by certain characterization techniques themselves containing above-bandgap illumination (above 2.1 eV) or heating (above 50 °C). We finally build a roadmap for obtaining accurate Raman spectra by using above-bandgap excitation lasers with low photon flux (below 1017 phs m-2 s-1) and below-bandgap excitation lasers measured at low temperatures (below -40 °C) to minimize the photoexcitation- and heat-induced ring-to-chain transitions.

Unveiling the Interfacial Species Synergy in Promoting CO2 Tandem Electrocatalysis in Near-Neutral Electrolyte.

The interfacial species-built local environments on Cu surfaces impact the CO2 electroreduction process significantly in producing value-added multicarbon (C2+) products. However, intricate interfacial dynamics leads to a challenge in understanding how these species affect the process. Herein, with ab initio molecular dynamics (AIMD) and finite element method (FEM) simulations, we reveal that the highly concentrated interfacial species, including the *CO, hydroxide, and K+, could synergistically promote the C-C coupling on the one-dimensional (1D) porous hollow structure regulated interfacial environment. The Cu-Ag tandem catalyst was then synthesized with the as-designed structure, exhibiting a high C2+ Faradaic efficiency of 76.0% with a partial current density of 380.0 mA cm-2 in near-neutral electrolytes. Furthermore, in situ Raman spectra validate that the 1D porous structure regulates the concentration of interfacial CO intermediates and ions to increase *CO coverage, local pH value, and ionic field, promoting the CO2-to-C2+ activity. These results provide insights into the design of practical ECR electrocatalysts by regulating interfacial species-induced local environments.

CNT Composite ß-MnO2 with Fiber Cable Shape as Cathode Materials for Aqueous Zinc-Ion Batteries.

Rechargeable aqueous zinc-ion batteries (AZIBs) have developed into one of the most attractive materials for large-scale energy storage owing to their advantages such as high energy density, low cost, and environmental friendliness. Nevertheless, the sluggish diffusion kinetics and inherent impoverished conductivity affect their practical application. Herein, the ß-MnO2 composited with carbon nanotubes (CNT@M) is prepared through a simple hydrothermal approach as a high-performance cathode for AZIBs. The CNT@M electrode exhibits excellent cycling stability, in which the maximum specific discharge capacity is 259 mA h g-1 at 3 A g-1, and there is still 220 mA h g-1 after 2000 cycles. The specific capacity is obviously better than that of ß-MnO2 (32 mA h g-1 after 2000 cycles). The outstanding electrochemical performance of the battery is inseparable from the structural framework of CNT and inherent high conductivity. Furthermore, CNT@M can form a complex conductive network based on CNTs to provide excellent ion diffusion and charge transfer. Therefore, the active material can maintain a long-term cycle and achieve stable capacity retention. This research provides a reasonable solution for the reliable conception of Mn-based electrodes and indicates its potential application in high-performance AZIB cathode materials.

Modulating the electronic structure of ion phthalocyanine-based molecular catalysts for electrocatalytic nitrogen reduction: a DFT study.

The highly localized Fe d orbital in ion phthalocyanine (FePc)-based molecular catalysts significantly hinders their electrocatalytic nitrogen reduction reaction (eNRR) performance. Herein, we theoretically designed a series of FePc-based molecules with adjacent metal phthalocyanine sites to form an asymmetric delocalized electronic structure on Fe centers, promoting the catalytic activity and lowering the overpotential of the eNRR, as well as suppressing the hydrogen evolution reaction (HER) side reaction.

Colloidal Zeta Potential Modulation as a Handle to Control the Crystallization Kinetics of Tin Halide Perovskites for Photovoltaic Applications.

Tin halide perovskites (THPs) have demonstrated exceptional potential for various applications owing to their low toxicity and excellent optoelectronic properties. However, the crystallization kinetics of THPs are less controllable than its lead counterpart because of the higher Lewis acidity of Sn2+, leading to THP films with poor morphology and rampant defects. Here, a colloidal zeta potential modulation approach is developed to improve the crystallization kinetics of THP films inspired by the classical Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. After adding 3-aminopyrrolidine dihydro iodate (APDI2) in the precursor solution to change the zeta potential of the pristine colloids, the total interaction potential energy between colloidal particles with APDI2 could be controllably reduced, resulting in a higher coagulation probability and a lower critical nuclei concentration. In situ laser light scattering measurements confirmed the increased nucleation rate of the THP colloids with APDI2. The resulting film with APDI2 shows a pinhole-free morphology with fewer defects, achieving an impressive efficiency of 15.13 %.

Facile Hydrogen-Bonding Assisted Crystallization Modulation for Large-area High-quality CsPbI2 Br Films and Efficient Solar Cells.

The thermally stable inorganic cesium-based perovskites promise efficient and stable photovoltaics. Unfortunately, the strong ionic bonds lead to uncontrollable rapid crystallization, making it difficult in fabricating large-area black-phase film for photovoltaics. Herein, we developed a facile hydrogen-bonding assisted strategy for modulating the crystallization of CsPbI2 Br to achieve uniform large-area phase-pure films with much-reduced defects. The simple addition of methylamine acetate in precursors not only promotes the formation of intermediate phase via hydrogen bonding to circumvent the direct crystallization of CsPbI2 Br from ionic precursors but also widens the film processing window, thus enabling to fabricate large-area high-quality phase-pure CsPbI2 Br film under benign conditions. Combining with stable dopant-free poly(3-hexylthiophene), the CsPbI2 Br solar cells achieve the record-high efficiencies of 18.14 % and 16.46 % for 0.1 cm2 and 1 cm2 active area, respectively. The obtained high efficiency of 38.24 % under 1000 lux illumination suggests its potential in indoor photovoltaics for powering the Internet of Things, etc.

Unconventional hcp/fcc Nickel Heteronanocrystal with Asymmetric Convex Sites Boosts Hydrogen Oxidation.

Developing non-platinum group metal catalysts for the sluggish hydrogen oxidation reaction (HOR) is critical for alkaline fuel cells. To date, Ni-based materials are the most promising candidates but still suffer from insufficient performance. Herein, we report an unconventional hcp/fcc Ni (u-hcp/fcc Ni) heteronanocrystal with multiple epitaxial hcp/fcc heterointerfaces and coherent twin boundaries, generating rugged surfaces with plenty of asymmetric convex sites. Systematic analyses discover that such convex sites enable the adsorption of *H in unusual bridge positions with weakened binding energy, circumventing the over-strong *H adsorption on traditional hollow positions, and simultaneously stabilizing interfacial *H2O. It thus synergistically optimizes the HOR thermodynamic process as well as reduces the kinetic barrier of the rate-determining Volmer step. Consequently, the developed u-hcp/fcc Ni exhibits the top-rank alkaline HOR activity with a mass activity of 40.6 mA mgNi-1 (6.3 times higher than fcc Ni control) together with superior stability and high CO-tolerance. These results provide a paradigm for designing high-performance catalysts by shifting the adsorption state of intermediates through configuring surface sites.

CO-Tolerant Hydrogen Oxidation Electrocatalysts for Low-Temperature Hydrogen Fuel Cells.

The severe performance degradation of low-temperature hydrogen fuel cells upon exposure to trace amounts of carbon monoxide (CO) impurities in reformate hydrogen fuels is one of the challenges that hinders their commercialization. Despite significant efforts that have been made, the CO-tolerance performance of electrocatalysts for the hydrogen oxidation reaction (HOR) is still unsatisfactory. This Perspective discusses the path forward for the rational design of CO-tolerant HOR electrocatalysts. The fundamentals of the CO-tolerant mechanisms on commercialized platinum group metal (PGM) electrocatalysts via either promoting CO electrooxidation or weakening CO adsorption are provided, and comprehensive discussions based on these strategies are presented with typical examples. Given the recent progress, some emerging strategies, including blocking CO diffusion with a barrier layer and developing non-PGM HOR catalysts, are also discussed. We conclude with a discussion of the strengths and limitations of these strategies along with the perspectives of the major challenges and opportunities for future research on CO-tolerant HOR electrocatalysts.

Pyridinic-N Regulated Electron Injection to Modulate *OH Adsorption at Fe-N-C Sites for an Efficient Oxygen Reduction Reaction.

To enhance the efficiency of oxygen reduction reaction (ORR) catalysts, precise control over the adsorption/desorption energy barriers of oxygen intermediates at atomically dispersed Fe-N-C sites is essential yet challenging. Addressing this, we employed a pyrolysis approach using a nitrogen-containing polymer to fabricate Fe single-atom (SA) catalysts embedded in a pyridinic-N enriched carbon matrix. This synthesis strategy yielded Fe SAs that demonstrated a superior electrochemical ORR performance, evidenced by an impressive half-wave potential of 0.941 V and a high limiting current density of 5.72 mA/cm2. Moreover, when applied in homemade Zn-air batteries, this premier catalyst exhibited exceptional specific capacity (720 mAh/gZn), peak power density (253 mW/cm2), and notable long-term stability. Theoretical insights revealed that the increased pyridinic-N content in the catalyst facilitated efficient electron transfer from N atoms to the Fe active sites, thus fine-tuning the d-band center and effectively controlling the adsorption energy barrier of *OH species. These mechanisms synergistically improve the ORR performance. Crucially, this fabrication method shows promise for adaptation to other transition metal-based SAs, including Co, Ni, and Cu, potentially establishing a versatile synthesis route for developing atomically dispersed catalyst systems in future applications.

Ultrasmall Pd nanoparticles supported on a metal-organic framework DUT-67-PZDC for enhanced formic acid dehydrogenation.

The highly dispersed ultrasmall palladium nanoparticles (Pd NPs) (1.7 nm) were successfully immobilized on a N-containing metal-organic framework (MOF, DUT-67-PZDC) using a co-reduction method, and it is used as an excellent catalyst for formic acid dehydrogenation (FAD). The optimized catalyst Pd/DUT-67-PZDC(10, 10 wt% Pd loading) shows 100% hydrogen (H2) selectivity and formic acid (FA) conversion at 60 °C, and the commendable initial turnover frequency (TOF) values of 2572 h-1 with the sodium formate (SF) as an additive and 1059 h-1 even without SF, which is better than most reported MOF supported Pd monometallic heterogeneous catalysts. The activation energy (Ea) of FAD is 43.2 KJ/mol, which is lower than most heterogeneous catalysts. In addition, the optimized catalyst Pd/DUT-67-PZDC(10) maintained good stability over five consecutive runs, demonstrating only minimal decline in catalytic activity. The outstanding catalytic performance could be ascribed to the synergistic corporations of the unique structure of DUT-67-PZDC carrier with hierarchical pore characteristic, the metal-support interaction (MSI) between the active Pd NPs and DUT-67-PZDC, the highly dispersed Pd NPs with ultrafine size serve as the catalytic active site, as well as the N sites on the support could act as the proton buffers. This work provides a new paradigm for the efficient H2 production of FAD by constructing highly active heterogeneous Pd-based catalysts using MOF supports.

KIF22 promotes multiple myeloma progression by regulating the CDC25C/CDK1/cyclinB1 pathway.

PURPOSE: Multiple myeloma (MM) is an incurable hematological malignancy characterized by clonal proliferation of malignant plasma B cells in bone marrow, and its pathogenesis remains unknown. The aim of this study was to determine the role of kinesin family member 22 (KIF22) in MM and elucidate its molecular mechanism. METHODS: The expression of KIF22 was detected in MM patients based upon the public datasets and clinical samples. Then, in vitro assays were performed to investigate the biological function of KIF22 in MM cell lines, and subcutaneous xenograft models in nude mice were conducted in vivo. Chromatin immunoprecipitation (ChIP) and luciferase reporter assay were used to determine the mechanism of KIF22-mediated regulation. RESULTS: The results demonstrated that the expression of KIF22 in MM patients was associated with several clinical features, including gender (P = 0.016), LDH (P < 0.001), ß2-MG (P = 0.003), percentage of tumor cells (BM) (P = 0.002) and poor prognosis (P < 0.0001). Furthermore, changing the expression of KIF22 mainly influenced the cell proliferation in vitro and tumor growth in vivo, and caused G2/M phase cell cycle dysfunction. Mechanically, KIF22 directly transcriptionally regulated cell division cycle 25C (CDC25C) by binding its promoter and indirectly influenced CDC25C expression by regulating the ERK pathway. KIF22 also regulated CDC25C/CDK1/cyclinB1 pathway. CONCLUSION: KIF22 could promote cell proliferation and cell cycle progression by transcriptionally regulating CDC25C and its downstream CDC25C/CDK1/cyclinB1 pathway to facilitate MM progression, which might be a potential therapeutic target in MM.