The efficient upgrading of low-concentration H2S into valuable chemicals remains an unresolved economic challenge, as conventional catalytic processes have difficulty handling low-concentration H2S. Herein, we develop a new decoupled sulfidation-reduction catalytic cycle strategy that transforms low-concentration H2S in blast furnace gas into high-value carbonyl sulfide (COS). To implement this strategy, we designed a novel Fe-modified carbon nanofiber catalyst (Fe-CNF-15) for efficient H2S enrichment, followed by a reduction step utilizing the CO present in blast furnace gas to produce COS. Fe-CNF-15 delivers a sulfur capacity of 0.926 mmol∙gcat.–1 and achieves a high COS yield of up to 96.13% over three consecutive cycles, demonstrating significant potential for high-value COS synthesis. The high performance of Fe-CNF-15 is attributed to the synergistic interplay between pyridinic nitrogen species and dispersed Fe sites, which creates favorable coordination environments for sulfur conversion. Density functional theory calculations reveal that the Fe3NC motif enables strong Fe-S interaction through Fe-d and S-p orbital coupling, regulates the adsorption of sulfur-containing intermediates, and promotes the overall H2S-to-COS conversion pathway. This work provides a feasible strategy for the conversion of low-concentration H2S and offers valuable insights for the design of efficient catalysts.
The co-combustion of sewage sludge (SS) with coal is a promising strategy for waste valorization; however, the impacts on gaseous pollutant emissions and heavy metal (HM) behavior remain inadequately characterized. This study investigates NO and SO2 release, the retention and extractability of six selected heavy metals (Mn, Zn, Cr, Ni, Cu, and Pb), and ash fusion characteristics during co-combustion. Co-firing with SS promoted early ignition and enhanced the coal combustion reactivity through the rapid release of volatiles, which facilitated fixed-carbon combustion; however, excessive SS blending reduced heat release owing to its low calorific value and high ash content. Concurrent in situ reductions of NO and SO2 were achieved. The enhanced combustion reactivity accelerated O2 consumption and promoted CO formation, creating a locally reducing atmosphere that contributed to the suppression of NO emissions. SO2 mitigation was associated with sulfur retention via the formation of stable sulfates by Ca-bearing minerals. Co-combustion enhanced the retention of Cr, Cu, Pb, and Zn in ash matrices while reducing their extractability, which is associated with HM-encapsulating silicate-, aluminosilicate-, and phosphate-rich phases. These refractory phases increased ash flow temperatures and inhibited liquid slag formation. Overall, SS/coal co-combustion reduces gaseous emissions and ash fusibility while stabilizing HMs in ashes.
Nickel-cobalt-based (NiCo) supercapacitors have garnered widespread attention owing to their high rate performance, safety, and low cost. However, conventional NiCo-layered double hydroxide (LDH) materials often exhibit low electrical conductivity, structural instability, and a limited number of exposed active sites. To address these issues, a reaction-time-controlled hydrothermal strategy was utilized to regulate the growth of an aluminum-doped nickel-cobalt LDH, enabling the formation of flower-like microstructures composed of interconnected nanoneedle arrays with improved ion-transport pathways and electrochemical performance. Notably, Al doping expanded the interlayer spacing, which facilitated rapid ion diffusion and improved the rate capability and charge–discharge efficiency. The electrochemical performance of the assembled device, including energy density, power density, and cycling stability, was systematically studied. Moreover, device-level optimization was achieved using strategies to widen the operating voltage window in asymmetric supercapacitors. The feasibility of the device was further supported by powering a light-emitting diode, electronic watch, calculator, and small electric fan, confirming its stable output performance.
Photocatalytic resource production, utilizing photo-generated electrons and holes for reactions like water splitting and uranium extraction from seawater, demands materials balancing broad light absorption and efficient charge separation. Two-dimensional sp2-carbon-conjugated covalent organic frameworks (sp2c COFs) emerge as highly promising photocatalysts due to their extended π-conjugation, enabling wide solar spectrum capture (including near-infrared) and enhanced carrier mobility. Current design strategies focus on incorporating photosensitive groups, constructing donor-acceptor heterojunctions, and optimizing high-conjugation to boost light harvesting and suppress charge recombination. Furthermore, designing specific active sites is also crucial for photocatalytic uranium extraction from seawater. This review summarizes the characteristics of different two dimensional sp2c COFs and their photocatalytic applications in photocatalytic hydrogen production and uranium recovery. Finally, it outlines future development trajectories for advancing sp2c COFs in sustainable photocatalysis.
Visible light-driven splitting of H2O for H2 offers a promising route for H2 production. However, highly active catalysts are still needed to efficiently split H2O into H2 production. Herein, spherical MoO2 was prepared by hydrothermal-annealing process, and the Pt loaded on MoO2 was reduced using a room-temperature discharge-driven reduction process (RT-DR), we fabricated Pt/CdS/MoO2 photocatalyst. Visible light-driven photocatalytic H2 production from water was achieved on Pt/CdS/MoO2. The highest catalytic efficiency was achieved when Pt loading was 0.25 wt % and RT-DR treatment time was 30 min, with the rate as high as 909.8 μmol∙h–1. After a continuous 20-h photocatalytic test, the H2 evolution rate could be maintained at 810 μmol∙h–1. X-ray photoelectron spectroscopy analysis suggests changes of the valence state of Pt nanoparticles by room-temperature discharge-driven reduction process. In this work, the reduction of H2O to H2 has been studied by density functional theory calculation on MoO2 (011) surfaces. On the surface, Pt2+ adsorbs H2O and decomposes them, while Pt0 adsorbs H and synthesizes them into H2, which allows the valence state regulation to have an important influence on the H2 evolution rate.
