Efficient catalytic removal of COS and H_(2)S over graphitized 2D micro-meso-macroporous carbons endowed with ample nitrogen sites synthesized via mechanochemical carbonization

Developing a suitable catalyst for the elimination of highly toxic carbonyl sulfide(COS)and hydrogen sulfide(H_(2)S) is of great significance in terms of industrial safety and environmental protection.We demonstrate here the facile synthesis of graphitized 2D micro-meso-macroporous carbons by one-step carbonization of a mixture of urea and glucose at 700–900℃.The as-synthesized graphitized catalysts,designated as 2DNHPC-x(x=urea/glucose mass ratio),are endowed with an ultra-high concentration(12.9–20.2 wt%)of stable and versatile nitrogen sites(e.g.pyrrole and pyridine)which are anchored on the surface via stable covalent bonding.As a result,the 2D-NHPC-x are active in catalytic hydrolysis of COS on pyrrolic N to H_(2)S,and the H_(2)S can be subsequently captured on pyridinic N and converted to elemental sulfur at ambient conditions over the same materials.Among the prepared catalysts,2D-NHPC-x can catalytically hydrolysize 91%of COS to H_(2)S at 30℃,whereas the conversion ratio over the common catalysts g-C_(3)N_(4)and Fe_(2)O_(3)are below 6.0%.Furthermore,these catalysts also exhibit H_(2)S conversion and sulfur selectivity of nearly 100%at 180℃with long-time durability,which is higher than those of the most reported carbonbased catalysts.In contrast,the H_(2)S capacities of activated carbon,ordered mesoporous carbons(OMC)and N-doped OMC are 3.9,1.5 and2.39 mmol g^(-1),respectively.Both the experimental and theoretical results are disclosed that 2D-NHPC-x are superior to the nitrogen-doped porous materials ever applied in simultaneous catalytic elimination of both COS and H_(2)S.

Surface plasmon resonance metal-coupled biomass carbon modified TiO_(2) nanorods for photoelectrochemical water splitting

Exploring efficient and stable photoanode materials is a necessary link to realize the practical application of solar-driven photoelectrochemical(PEC)water splitting.Hence,we prepared rutile TiO_(2) nanorods,with a width of 50 nm,which was growth in situ on carbon cloth(TiO_(2)@CC)by hydrothermal reaction.And then,Ag nanoparticles(NPs)and biomass N,S-C NPs were chosen for the additional modification of the fabricated TiO_(2) nanorods to produce broccoli-like Ag-N,S-C/TiO_(2)@CC nanocomposites.According to the result of ultraviolet-visible diffuse reflectance spectroscopy(UV-vis)and PEC water splitting performance tests,Ag-N,S-C/TiO_(2)@CC broadens the absorption region of TiO_(2)@CC from the ultraviolet region to the visible regio n.Under AM 1.5 G solar light irradiation,the photocurrent density of Ag-N,S-C/TiO_(2)@CC is 89.8μA·cm^(-2),which is 11.8 times higher than TiO_(2)@CC.Under visible light irradiation,the photocurrent density of Ag-N,S-C/TiO_(2)@CC reaches to 12.6μA·cm^(-2),which is 21.0 times higher than TiO_(2)@CC.Moreover,Ag-N,S-C/TiO_(2)@CC shows a photocurrent responses in full pH range.It can be found that Ag NPs and N,S-C NPs play key roles in broaden the absorption range of TiO_(2) nanorods to the visible light region and,promote the occurrence of PEC water oxidation reaction due to the surface plasmon resonance effect of Ag NPs and the synergistic effect of N,S-C NPs.The mechanism demonstrated that Ag-N,S-C/TiO_(2)@CC can separate the photogenerated electron-hole pairs effectively and transfer the photogenerated electrons to the photocathode(Pt plate)in time.This research provides a new strategy for exploration surface plasma metal coupled biomass carbon materials in the field of PEC water splitting.

Efficient and reversible separation of NH_(3) by deep eutectic solvents with multiple active sites and low viscosities

The efficient separation and collection of ammonia(NH_(3))during NH_(3) synthesis process is essential to improve the economic efficiency and protect the environment.In this work,ethanolammonium hydrochloride(EtOHACl)and phenol(PhOH)were used to prepare a novel class of deep eutectic solvents(DESs)with multiple active sites and low viscosities.The NH_(3) separation performance of EtOHACl+PhOH DESs was analyzed completely.It is figured out that the NH_(3) absorption rates in EtOHACl+PhOH DESs are very fast.The NH_(3) absorption capacities are very high and reach up to 5.52 and 10.74 mol·kg1 at 11.2 and 100.4 kPa under 298.2 K,respectively.In addition,the EtOHACl+PhOH DESs present highly selective absorption of NH_(3) over N_(2) and H_(2) and good regenerative properties after seven cycles of absorption/desorption.The intrinsic separation mechanism of NH_(3) by EtOHACl+PhOH DESs was further revealed by spectroscopic analysis and quantum chemistry calculations.

Enhancing the activity of MoS_(2)/SiO_(2)-Al_(2)O_(3) bifunctional catalysts for suspended-bed hydrocracking of heavy oils by doping with Zr atoms

Developing catalysts with not only hydrogenation activity but also cracking activity is very important for the advancement of suspended-bed hydrocracking technology.Within this respect,MoS_(2)/SiO_(2)-Al_(2)O_(3)bifunctional catalyst is a kind of typical catalysts with both hydrogenation and cracking activity.Herein,a series of Zr-doped SiO_(2)-Al_(2)O_(3)mixed oxides were synthesized by a sol-gel coupled with hydrothermal method.The synthesized mixed oxides were characterized for chemical structures and acidic properties.It is found that doping SiO_(2)-Al_(2)O_(3)with Zr atoms significantly increases the numbers of acidic sites.The Zr-doped SiO_(2)-Al_(2)O_(3)mixed oxides were then combined with dispersed MoS_(2),which was in-situ produced from oil-soluble Mo precursors,to fabricate a novel kind of bifunctional catalysts for suspended-bed hydrocracking of heavy oils.Owing to the significantly increased numbers of acidic sites in Zr-doped SiO_(2)-Al_(2)O_(3)mixed oxides,corresponding bifunctional catalysts demonstrate much enhanced activity for suspended-bed hydrocracking of heavy oils in relative to MoS_(2)/SiO_(2)-Al_(2)O_(3)bifunctional catalysts.

Numerical study of inhibition mechanism of high-pressure hydrogen leakage self-ignition with the addition of ammonia

Hydrogen and ammonia have attracted increasing attention as carbon-free fuels.Ammonia is considered to be an effective energy storage and hydrogen storage medium.However,a small amount of unremoved NH3 is still present in the product during the decomposition of ammonia to produce hydrogen.Therefore,it is very essential to investigate the self-ignition of hydrogen-ammonia mixtures in order to accommodate the various scenarios of hydrogen energy applications.In this paper,the effect of NH3 addition on the self-ignition of high-pressure hydrogen release is numerically investigated.The RNG k-εturbulence model,EDC combustion model,and 213-step detailed NH_(3)/H_(2) combustion mechanism are used.CHEMKIN-Pro programs for zero-dimensional homogeneous and constant volume adiabatic reactor models are used for sensitivity analysis and ignition delay time of the chemical reaction mechanism.The results showed that the minimum burst pressure required for self-ignition increased significantly after the addition of ammonia.The maximum temperature and shock wave intensity inside the tube decreases with increasing ammonia concentration.The ignition delay time and H,HO2,and OH radicals reduce with increasing ammonia concentration.H and HO2 radicals are suggested as indicators for tracking the second and third flame branches,respectively.

An Ammonia-Hydrogen Energy Roadmap for Carbon Neutrality:Opportunity and Challenges in China

1.Opportunities and a bottleneck in the hydrogen energy industry Hydrogen(H_(2))is a carbon-free energy carrier with a wide range of application scenarios that was first emphasized in the Report on the Work of the Government in 2019 in China.In March 2021,President Xi Jinping reiterated that China pledges to achieve the goals of peak carbon emissions by 2030 and carbon neutrality by 2060.

Hydroxyapatite-modified micro/nanostructured titania surfaces with different crystalline phases for osteoblast regulation

Surface structures and physicochemical properties critically influence osseointegration of titanium(Ti)implants.Previous studies have shown that the surface with both micro-and nanoscale roughness may provide multiple features comparable to cell dimensions and thus efficiently regulate cell-material interaction.However,less attention has been made to further optimize the physicochemical properties(e.g.,crystalline phase)and to further improve the bioactivity of micro/nanostructured surfaces.Herein,micro/nanostructured titania surfaces with different crystalline phases(amorphous,anatase and anatase/rutile)were prepared and hydroxyapatite(HA)nanorods were deposited onto the as-prepared surfaces by a spin-assisted layer-by-layer assembly method without greatly altering the initial multi-scale morphology and wettability.The effects of crystalline phase,chemical composition and wettability on osteoblast response were investigated.It is noted that all the micro/nanostructured surfaces with/without HA modification presented superamphiphilic.The activities of MC3T3-E1 cells suggested that the proliferation trend on the micro/nanostructured surfaces was greatly influenced by different crystalline phases,and the highest proliferation rate was obtained on the anatase/rutile surface,followed by the anatase;but the cell differentiation and extracellular matrix mineralization were almost the same among them.After ultrathin HA modification on the micro/nanostructured surfaces with different crystalline phases,it exhibited similar proliferation trend as the original surfaces;however,the cell differentiation and extracellular matrix mineralization were significantly improved.The results indicate that the introduction of ultrathin HA to the micro/nanostructured surfaces with optimized crystalline phase benefits cell proliferation,differentiation and maturation,which suggests a favorable biomimetic microenvironment and provides the potential for enhanced implant osseointegration in vivo.