Xingxing Chen

Bismuth vanadate (BiVO4) photoanodes suffer from sluggish oxygen evolution kinetics and severe charge recombination. Although Ni-based cocatalysts are widely used, low conductivity and insufficient active-site density remain bottlenecks. Herein, atomically dispersed Pt sites are constructed in NiOx-modified BiVO4 to enable light-driven dynamic interfacial polarization and adaptive electronic modulation for photoelectrochemical (PEC) water splitting. Mechanistic investigations based on in situ spectroscopies suggest that atomically dispersed Pt sites efficiently mediate photogenerated holes. Transient electron-deficient states in the valence orbitals drive rapid charge separation, while continuous electron compensation preserves a stable electron-shielded core for optimal catalytic turnover. Density functional theory (DFT) calculations further show that electronic metal-support interaction (EMSI) redistributes the free energy landscape across all proton-coupled electron transfer (PCET) steps, shifting the potential-determining step (PDS) from *OH to *OOH formation and mitigating linear scaling constraints. The optimized photoanode yields 6.30 mA/cm2 at 1.23 V vs the reversible hydrogen electrode (RHE), with charge injection/separation efficiencies of 96.2%/86.9% and a near-ideal 95% Faradaic efficiency (FE). This work offers a robust electronic regulation strategy for high-performance PEC water splitting.

To address the pressing need for efficient azo dye wastewater treatment, a novel self-supporting electro-Fenton (EF) cathode (Zr-C/NFME) was fabricated via electrospinning and programmed carbonization using UiO-66 as a precursor. UiO-66-derived Zr–O bonds facilitate the uniform exposure of Zr sites. Combined EPR and O 1s XPS analyses verify the dynamic generation of oxygen vacancies during reaction, which promotes interfacial electron transfer, accelerates the Fe3+/Fe2+ redox cycle, and enhances the in-situ H2O2 activation. EPR and quenching tests reveal that ·OH dominates degradation, with ·O2- playing a synergistic role. Benefiting from these integrated advantages, Zr-C/NFME achieves 94.7% removal of methyl orange (MO) within 30 min, demonstrating broad pH adaptability, applicability to diverse dyes, and stable performance over 5 consecutive cycles. TOC and COD removal rates reach 40.7% and 43.5% after 1 h. DFT and LC-MS identified azo bonds, tertiary amines, and sulfonic groups as primary radical attack sites, and ECOSAR assessment confirms reduced ecotoxicity of intermediates. This study provides a novel strategy for designing high-performance, stable self-supporting EF cathodes with promising application in organic wastewater remediation.

Methyl orange (MO), a typical azo dye in textile wastewater, presents a serious threat to aquatic ecosystems and human health. Although Electro-Fenton (EF) technology exhibits unique advantages in treating recalcitrant organics, conventional cathodes often suffer from issues such as active site agglomeration, insufficient catalytic activity, and compromised stability. Herein, a self-supporting zirconium-contained carbon nanofiber membrane electrode (Zr-C/NFME) was synthesized via electrospinning carbonization using UiO-66 (a zirconium-based metal-organic framework) as a precursor. This binder-free design effectively eliminates active site masking, while the UiO-66-derived Zr–O bonds effectively provide a stable coordination environment and efficient electron transfer channels. The Zr4+ Lewis acid sites induce oxygen vacancy formation, which effectively accelerate the Fe3+/Fe2+ redox cycle, thereby markedly boosting H2O2 activation efficiency and hydroxyl radicals (·OH) yield. The three-dimensional porous network with uniformly dispersed ZrO2 sites enables a 94.7% MO degradation within 30 minutes and demonstrates wide pH adaptability (3–11) and excellent stability over 7 consecutive cycles. EPR and quenching tests confirm ·OH as the primary reactive species, with ·O2- playing a synergistic role in the degradation process. DFT calculations and LC-MS analysis identify the azo bond, tertiary amine, and sulfonic group as the preferential attack sites, elucidating complete mineralization pathways. ECOSAR assessment reveals significantly reduced ecotoxicity of intermediates. This eco-friendly self-supporting electrode design provides a novel solution for the green treatment of azo dye wastewater with promising engineering applications.

In response to the urgent demand for efficient organic dye wastewater treatment, this study introduces a novel free-standing electro-Fenton cathode with atomic-level Fe sites (FeBNC/CFM). The MIL-101(Fe) precursor is rapidly synthesized via microwave assistance, followed by the fabrication of a three-dimensional network membrane electrode through electrospinning and programmed temperature-controlled carbonization. X-ray absorption fine structure (XAFS) analysis reveals that the introduction of hexagonal boron nitride (h-BN) promotes atomic-level dispersion, forming Fe-N/Fe-B coordination motifs. This structural innovation significantly enhances hydrophilicity and stability, enabling exceptional performance in electro-Fenton degradation. The cathode rapidly removed 90.6% of Rhodamine B (RhB) within 5 min, achieving a removal efficiency of 98.6% in 10 min. Moreover, it demonstrated excellent performance in removing not only various dyes but also RhB-spiked actual wastewater. Hydroxyl radicals (·OH) and superoxide radicals (·O₂^-) are the primary reactive oxygen species (ROS), with ·OH exhibiting significantly higher reactivity. The active sites and degradation pathways of the RhB molecule are further elucidated via density functional theory (DFT) and liquid chromatography-mass spectrometry (LC-MS) analyses. Notably, toxicity assessment indicates low environmental risk from most of the intermediates, indicating negligible potential for secondary environmental contamination. This study provides a novel strategy for designing high-performance, stable electro-Fenton cathodes showing broad application potential in organic wastewater remediation.

Coke, as an essential metallurgical raw material, is widely used in iron and steel production. To investigate the pyrolysis behavior and cross-linking reactions during the pyrolysis of coking coal, pyrolysis experiments were conducted in a quartz-tube fixed-bed reactor placed in an electric furnace. The yields and compositions of the pyrolysis products were systematically analyzed. Gaseous and tar components generated at different pyrolysis stages were characterized using gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The semi-coke was examined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results indicated that the yields of tar from coking coal pyrolysis have a notable impact on the cross-linking reactions occurring during the coal pyrolysis process. The structural differences between Malan coal (ML) and Tunlan coal (TL) coals underlie their distinct behaviors in cross-linking intensity, tar evolution profiles, and coke-forming properties. For high-volatile, highly fluid ML coal, the release of the aliphatic compounds in tar volatiles remains relatively low at the temperature of maximum fluidity, which is beneficial to the cross-linking reactions. In contrast, for TL coal with lower volatility and fluidity, substantial H₂ emission during the early pyrolysis stage promotes cross-linking reactions. This study provides new insights into the temperature-dependent evolution of cross-linking reactions during coking coal pyrolysis.

The structure and properties of coke are of significant importance in the metallurgical industry. Coke samples were prepared from different bituminous coals at varying temperatures using a one-sided heating furnace. The evolution of carbon structure during the coking process was investigated by X-ray diffraction (XRD) and Raman spectroscopy. The correlations between carbon structure parameters and the properties of the coal and coke were investigated during coke formation. The results indicated that with increasing temperature, the values of L_a, L_c, N, n, and f_a were increased, while the d₀₀₂ values decreased. The L_a/L_c ratio was expanded twice more than raw coal due to condensation and cross-linking reactions, indicating compaction of the carbon structure and the formation of larger aromatic units. A negative correlation was observed between L_c and the Coke Reactivity Index (CRI), whereas a positive correlation was found between L_a and Coke Strength after Reaction (CSR), which mean that coke properties improve with increasing L_c. Specifically, when L_c exceeds 2.4 nm, and L_a lies between 5 and 5.5 nm, the coke exhibits higher quality. The quality of coke is strongly affected by the structural evolution of carbon during the coal coking process.