Supawadee Namuangruk

Mercury removal from aqueous and hydrocarbon media requires sorbents that combine strong binding affinity with sufficient pore accessibility and mass transfer. In this study, granular activated carbon (GAC) was treated with 1,2-ethanedithiol through an oxidant-free, thermally initiated thiol–ene-type radical route to produce sulfur-functionalized GAC (S-GAC) with different sulfur loadings. The sulfur content increased from 3.38 to 15.07 wt %, while the BET specific surface area decreased from 859 to 25 m2 g–1, indicating progressive pore occupation and blockage. At low initial Hg(II) concentration, sulfur functionalization enhanced Hg(II) removal in both aqueous solution and synthetic gas condensate, with 10–30%S-GAC achieving very low residual Hg(II) concentrations. At elevated aqueous Hg(II) concentrations, pristine GAC exhibited faster initial uptake and approached a plateau earlier, whereas S-GAC showed slower but sustained adsorption. At approximately 40 mg L–1 Hg(II) concentration, 5%S-GAC and 10%S-GAC ultimately achieved slightly higher observed uptakes than pristine GAC, while at approximately 120 mg L–1 pristine GAC retained the highest uptake over the monitored period. These results show that the effect of sulfur functionalization depends on Hg(II) loading, contact time, and the balance between Hg–S affinity and pore accessibility. XPS, Hg L3-edge XAS, and DFT calculations were consistent with sulfur-containing Hg coordination environments and more favorable interaction near sulfur-rich edge configurations. Sulfur functionalities remained strongly retained over pH 2–10, although regeneration performance decreased with repeated cycles. Overall, Hg(II) capture reflects the combined effects of sulfur-site affinity, pore accessibility, mass transfer, Hg(II) loading, and the treatment matrix.

Non-polymerizable cyclic thioether acts as a reactive monomer in ROCOP of cyclic anhydrides and epoxides, giving unexpected (ABC) _n poly(diester-thioether)s with enhanced Au ³⁺ and Fe ³⁺ binding and accelerated degradation.

The performance of electrochemical advanced oxidation processes (EAOP) is governed by the nature of the electrode material, with catalytic activity intrinsically linked to the generation of hydroxyl radicals that initiate oxidation. Here, using boron-doped diamond (BDD), widely recognized for its high hydroxyl radical yield, and platinum (Pt) as a contrasting reference electrode, we combine grand canonical density functional theory with machine learning molecular dynamics to investigate the generation, stabilization, and decay of OH• radicals at electrochemical interfaces. For BDD and Pt systems examined here, our calculations support an outer-sphere electron transfer pathway for OH• generation and indicate that the key difference between the two electrodes lies in the subsequent interfacial consumption of OH•. Although hydroxyl binding on BDD is stronger than on Pt, surface-bound OH* species on BDD are chemically inert and do not exhibit radical character. As a result, BDD suppresses OH• recombination with surface OH*, increasing the relative availability of OH• in the interfacial region. In contrast, on Pt electrodes, OH* possesses radical character that promotes rapid radical recombination and consequently limits catalytic oxidation efficiency. This study identifies suppressed interfacial OH• recombination as a key factor controlling OH• availability and EAOP performance, suggesting that surface shielding against radical quenching could serve as a design strategy for next-generation oxidation anodes.

This work presents an approach to enhance the catalytic performance of a CoII-phthalocyanine (CoPc)-based polymer for electrochemical CO2 reduction (ECO2R) by introducing a 4-dimethylaminopyridine (DMAP) axial ligand on a Co metal center. Following a previous study on 4-aminophenoxy-substituted CoPc monomer (CoPc-1) and polymer (p-CoPc-1) catalysts, a target DMAP-coordinated CoPc polymer (p-CoPc-2) was prepared by two practical routes. One included DMAP axial coordination of CoPc-1 followed by electropolymerization of the resulting CoPc-2 monomer, while the other involved DMAP treatment of a p-CoPc-1 film. Ultraviolet−visible (UV−vis) spectrophotometry, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS) confirmed the successful preparation of CoPc-2 and its polymer films. Results from catalytic performance evaluation revealed that the polymer from the first route (p-CoPc-2A) exhibited superior CO2-to-CO conversion performance compared to that from the second one (p-CoPc-2B). The p-CoPc-2A-catalyzed ECO2R in an H-cell at an applied potential of −1.20 V vs NHE (−0.77 V vs RHE) showed current density (jCO) and Faradaic efficiency of CO formation (FECO) of 8.13 mA·cm−2 and 99%, respectively, corresponding to a turnover frequency (TOFCO) of 2.84 s−1. At this optimal potential, p-CoPc-2A exhibited an average FECO of 96% with a turnover number (TONCO) of 4.0 × 106 over 40 h of electrolysis. In a flow cell, p-CoPc-2A showed superior catalytic performance compared to p-CoPc-1 by maintaining the average FECO of 95% and j of 167 mA·cm−2 for 25 h. Electrochemical impedance spectroscopy (EIS) and in situ XAS studies reflected a critical role of the DMAP ligand in promoting interfacial charge transfer, charge transport, and stabilization of the local coordination environment around the Co metal center during the ECO2R. Furthermore, the theoretical calculation showed the impact of the DMAP coordination in elevating the orbital energy level, lowering the free-energy barrier for *COOH intermediate formation, and stabilizing the low-spin reaction pathway.

Electrocatalytic oxidation of 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA) offers a sustainable route to bio‐based plastics that can replace petroleum‐derived PET. Here, we systematically compare NiOOH and Fe−, Co−, and Cu‐doped NiOOH electrocatalysts synthesized by pulsed electrodeposition with matched loadings and dopant distributions, enabling a direct one‐to‐one assessment of dopant effects on HMFOR in alkaline media. Among all catalysts, NiFeOOH delivers the highest activity and selectivity across the full potential range, reaching an FE _FDCA of 87.42% and an FE _HMFOR of 98.85% at 1.53 V versus reversible hydrogen electrode. Scaling the electrode area fivefold achieves near‐quantitative HMF conversion (99.98%) with a 95.45% FDCA yield over 6 h while maintaining excellent durability. Mechanistic investigation via potential‐dependent product analysis, in situ Raman spectroscopy, spontaneous kinetics, and density functional theory reveals dopant‐specific functions: Fe strongly tunes the Ni ³⁺ electronic structure to weaken Ni ³⁺ –O bonding, enhance substrate adsorption, and accelerate charge transfer; Co primarily increases electrochemical surface area, boosting site density but not intrinsic site reactivity; and Cu alters the rate‐determining step, redirecting the reaction pathway. These insights show that different dopants offer distinct design levers in Ni‐based HMF oxidation reaction (HMFOR) catalysts and motivate multidopant strategies to jointly tune electronic structure, morphology, and reaction pathways for improved performance.

Electropolymerization of a novel Co ^II -phthalocyanine bearing 4-aminophenoxy α-substituents forms a robust polymer film enabling highly selective and efficient electrochemical CO ₂ to CO conversion.

Electric field perpendicular to the surface enhanced the reactivity of the 2*CO → *OC–CO reaction on graphyne by electron migration to the C–C coupling region. Boron doping to graphyne showed a weaker dependence on the electric field.

CALF-20 is a metal-organic framework (MOF) that is known for its exceptional CO₂ selectivity under humid conditions. However, the molecular mechanism underlying its humidity-induced structural phase transitions and how water and CO₂ compete at the molecular level remain unclear. In this work, we developed a machine learning potential (MLP) with first-principles accuracy to investigate how water dynamics drive the transition from the open-pore (OP) to the closed-pore (CP) phase. We identify that water coordination at the Zn node forms hydrogen-bonded water dimers and trimers along the [011] diffusion channel, which are critical for the OP-CP phase transition. In the CP structure, these Zn-bound water networks exhibit residence times exceeding hundreds of picoseconds and occupy approximately half of the Zn nodes, reproducing previous experiments for the first time. Remarkably, preadsorbed CO₂ disrupts this water network. This effect is further supported by diffuse reflectance infrared Fourier transform spectroscopy, which reveals suppressed O-H stretching signals in CO₂ preloaded samples, indicating the inhibition of hydrogen-bonded water cluster formation. These findings provide a mechanistic explanation for the experimentally observed delay in the water uptake under competitive CO₂/H₂O adsorptions. Moreover, our MLP simulations accurately reproduce the water adsorption isotherm and experimental X-ray diffraction patterns of the α, β, τ, and γ phases, establishing a direct link between the microscopic structure and the macroscopic phase behavior observed in experiments. This study provides molecular-level insights into humidity-induced transitions in flexible MOFs and demonstrates a simulation framework for modeling guest-responsive behavior in soft porous materials.

A calcium catalyst was found to be highly active for ROP of lactide. DFT calculations revealed that hydrogen-bonding of N–H moieties with lactide and large metal size are responsible for high catalytic performance.