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A cascade of in situ chemical conversion of HCO3-to CO2and CO2electrochemical reduction to CO in a flow cell is achieved with a tailored Ni-N-S single atom catalyst.

Heterogeneous structure supported Ni-Fe-P-Ni(OH)2/NF catalysts were fabricated by electroless deposition. The as-prepared composite catalyst exhibits remarkable electrocatalytic properties towards the hydrogen evolution reaction, requiring a low overpotential of 201 mV at a current density of −100 mA cm−2. Notably, the Ni-Fe-P-Ni(OH)2/NF also demonstrates exceptional oxygen evolution performance, achieving a current density of 100 mA cm−2with only 294 mV overpotential. Moreover, its performance in overall water splitting, serving as both a cathode and an anode, showcases a significantly low overpotential of 1.51 V at a current density of 10 mA cm−2. Following a 24-hour chronopotentiometry stability test at a current density of 50 mA cm−2, the dual electrodes maintain excellent performance for overall water splitting. This work provides a feasible method for the research and development of efficient and stable overall water splitting catalysts.

Cadmium (Cd) contamination in paddy soils poses a serious threat to agricultural production and human health. In this study, cysteine was selected as the leaching agent for remediating Cd-contaminated paddy soils because of its effective, low cost and ecofriendly characteristics. Microcosmic simulation experiment was using to investigate the fate of Cd and elucidate the transformation mechanism of Cd in the key components of paddy soil under cysteine leaching. Results showed that the total Cd removal rate of paddy soils reached 46.8–87.4% under the optimal conditions. This was mainly attributed to the decrease of exchangeable fraction (F1), carbonate bound fraction (F2), iron/manganese-bound fraction (F3) and organic matter bound fraction (F4) of Cd. After cysteine leaching, soil fertility was promoted due to the increase in nitrate nitrogen (NN), ammonia nitrogen (AN), available phosphorus (AP) and organic matter (OM). pH, CaCO3, available potassium (AK), NN, AP, amorphous iron oxides (Feo) were the main contributors to Cd fractionation transformation. The desorption of Cd from ferrihydrite (Fh) and goethite (Gt) surfaces is hypothesized to stem from dual mechanisms: the dissolution due to the low solution pH and the reducibility of cysteine, which facilitated the conversion of Fh and Gt to hematite (Hm). And the -SH complexation also ascribed to the activation of Cd bound by Fe-OH in Fh and Gt and oxygen-containing functional groups in humic acid (Ha). For chlorite (Ch), the primary driver for Cd desorption was identified as an ion-exchange process, whereby electrostatically adsorbed Cd2+were replaced by H+produced by cysteine protonation.

Designing high-performance hydrogen evolution reaction (HER) catalysts is crucial for seawater splitting. Herein, we demonstrate a facile Anderson-type polyoxometalate-assisted synthesis route to prepare defect-rich doped 1T/2H-MoSe2nanosheets. As demonstrated, the optimized defect-rich doped 1T/2H-MoSe2nanosheets display low overpotentials of 116 and 274 mV to gain 10 mA cm–2in acidic and simulated seawater for the HER, respectively. A magnesium (Mg)/seawater battery was fabricated with the defect-rich doped 1T/2H-MoSe2nanosheet cathode, displaying the highest power density of up to 7.69 mW cm–2and stable galvanostatic discharging over 24 h. The theoretical and experimental investigations show that the superior HER and battery performances of the heteroatom-doped MoSe2nanosheets are attributed to both the improved intrinsic catalytic activity (effective activation of water and favorable subsequent hydrogen desorption) and the abundant active sites, benefiting from the favorable catalytic factors of the doped heteroatom, 1T phase, and defects. Our work presents an intriguing structural modulation strategy to design high-performance catalysts toward both HER and Mg/seawater batteries.

Low cost, highly selective and efficient electrocatalysts for CO2reduction reaction (CO2RR) is crucial for lowering the global carbon footprint and mitigating energy shortages. Here, we first report a highly selective and efficient electrocatalyst for CO2RR to CO using a surface-regulated Ni nanoparticles supported on N-doped CMK-3 (N,O-Ni/CMK3). Compared with most Ni metal catalysts previously reported with severe competitive hydrogen evolution during the CO2RR, the N,O-Ni/CMK3 catalyst presents a superior CO faradaic efficiency of about 97%, a high CO partial current density (13.01 mA cm−1) and turnover frequency (4.25 s−1). The comprehensive characterization provides evidence that the N,O co-regulated Ni acts as the active center. Taking advantage of the N, O co-regulated chemical environment, N,O-Ni/CMK3 also displays a decent stability at negative potentials. Our work paves a novel approach for developing transition metal catalysts for CO2RR with enhanced activity and selectivity viaregulating surface chemical environment.

The S vacancy generated in the phosphating process of ZnxCd1−xS/CoO QDs plays key roles in the enhancement of ZnxCd1−xS/CoP QDs for photocatalytic hydrogen evolution under visible light.

Filling the in situ-generated vacancies with metal cations captured by C−N bonds of defect-rich 3D carbon nanosheets produces a superior ORR/OER bifunctional catalyst for a rechargeable Zn-air battery.

Metal d-band configuration is decisive to the interaction of metals with reactants and intermediates, therefore often governs the catalytic activity. Herein, we for the first time demonstrate a family of alkali tungsten bronzes (MxWO3, M = Na, K, Rb, Cs and 0

Transition metal phosphides are a class of promising electrocatalysts for hydrogen evolution reaction (HER) to replace noble metals. In this work, we for the first time synthesize carbon supported CoP nanoparticles with the average particle sizes from 3.3 to 9.2 nm, via a solvothermal process followed by low-temperature topological phosphorization, and the size-dependent HER activity of the CoP is investigated by virtue of TEM, XRD, XPS and the electrochemical techniques. It is discovered that the 9.2nm-CoP particles possess high intrinsic HER catalytic activity as compared to the 3.3nm-CoP, although the smaller one displays a high mass activity due to the large surface area. Detailed studies manifest that the small CoP particles suffer from serious oxidation once exposing to air. In contrast, most cobalt remains in the quasi-metallic state in the relatively large CoP particles, which is beneficial for the desorption of Hads, the rate determining step of the HER process over CoP surface. In addition, the low charge transfer resistance across the liquid/solid interfaces also contributes to the excellent HER activity of the relatively large CoP particles.

Abstract: The development of electrocatalysts with high activity and low Tafel slope for overall water splitting has become a crucial challenge to exploit the sustainable energy. Herein, we construct a Fe–Co–P–Gr catalyst on nickel foam (NF) support through electroless composite plating to realize the co-deposition of Fe–Co–P alloys and graphene quantum dots. Interestingly, graphene quantum dots exhibit obvious effects on electron mobility and active sites of Fe–Co–P–Gr/NF catalyst. In oxygen evolution reaction, the Fe–Co–P–Gr/NF catalyst exhibits a small overpotential of 230 mV at 10 mA cm−2and fast kinetics with Tafel slope of 37.8 mV dec−1. Meanwhile, the Fe–Co–P–Gr/NF also has a superior hydrogen evolution reaction performance in 1.0 M KOH. Compared with the Fe–Co–P alloys, the Fe–Co–P–Gr/NF both as the anode and cathode require only 1.58 V to reach a current density of 10 mA cm−2. The successful preparation of Fe–Co–P–Gr/NF electrode through electroless composite deposition provides a new path to manufacture electrocatalysts for overall water splitting. Graphic Abstract:

Solar light driven hydrogen production from water splitting and oxidation of biomass-derivatives is attractive for the conversion of solar energy to high value-added chemicals. The fabrication of heterostructure photocatalysts with matched band structure between two semiconductors is a promising approach for efficient photocatalysis. In this work, a novel In2O3/In2S3heterostructured hollow fiber photocatalyst was successfully fabricated through two-step ion exchange and chemical bath deposition methods, where the In2S3nanoparticles anchored on the surface of In2O3hollow fibers via strong interfacial interaction between In2O3(222) facet and In2S3(220) facet. The photocatalyst was used for efficient visible-light-driven photocatalytic hydrogen production integrated with selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). Compared with pristine In2O3and In2S3, the optimal In2O3/In2S3heterostructure exhibits an enhanced photocatalytic hydrogen production rate (111.2 ​μmol ​h−1 ​g−1) and HMF conversion efficiency (56%) and DFF selectivity (68%) under visible light irradiation. The experimental and theoretical investigations illustrate the phase interface between well matched In2O3(222) facet and In2S3(220) facet gives rise to facilitated photogenerated charge separation and transfer. This study presents the development of high-performance heterostructured photocatalysts for high efficient hydrogen production coupling with biomass oxidation.

Background: Roxadustat is an oral hypoxia inducing factor-prolyl hydroxylase inhibitor (HIF-PHI) that regulates iron metabolism in patients with chronic kidney disease (CKD) primarily by reducing hepcidin levels and mobilizing internal iron stores. More data are needed to demonstrate the efficacy of roxadustat in regulating iron metabolism in patients with peritoneal dialysis (PD) compared with erythropoiesis stimulating agents (ESAs). Methods: This prospective cohort study enrolled PD patients with a mean hemoglobin level of 60–100 g/L. All subjects were randomized into two groups at a ratio of 2:1 the roxadustat group (106 cases), and the ESA group (53 cases). The primary endpoint was the change in the iron biomarker levels and the proportion of patients with absolute iron deficiency and functional iron deficiency. Results: Compared with ESAs, roxadustat significantly decreased hepcidin level (difference, − 20.09 ng/mL; 95% CI, − 30.26 to − 9.92), attenuated the increase in serum soluble transferrin receptor (sTFR) level (difference, − 7.87 nmol/L; 95% CI, − 12.11 to − 3.64), and reduced the proportion of patients with functional iron deficiency (roxadustat, 11.43%; ESA, 33.33%). There was no significant difference in safety of the two groups over the duration of the study. Conclusions: Compared with ESA group, roxadustat group showed significant differences in all iron biomarker levels except serum ferritin (sFt) and transferrin saturation (TSAT). These results suggest that roxadustat was superior to ESAs as a therapy for iron metabolism in PD patients. Graphical abstract:

Cobalt oxides, including spinel Co3O4and rock-salt CoO, have been widely reported as promising catalysts for oxygen reduction reaction (ORR). However, three types of cobalt ions, i.e., Co2+in the tetrahedral site (Co2+Td), Co3+in the octahedral site (Co3+Oh), and Co2+in the octahedral site (Co2+Oh), are included in these oxides, and the roles of cobalt geometric occupancy and valance states have remained elusive. Here, for the first time, we investigated the effects of cobalt geometric occupancy on the ORR activity by substituting Co2+Tdand Co3+Ohof Co3O4with inactive Zn2+and Al3+, respectively. The ORR activity decreases in the order of Co3O4(Co3+Oh, Co2+Td) < ZnCo2O4(Co3+Oh) ≪ CoAl2O4(Co2+Td) in accordance with the ORR overpotentials at the current density of 0.1 mA cmOx–2. Furthermore, by comparatively investigating the activity and stability of Co3O4(Co3+Oh) and CoO (Co2+Oh) nanoparticles, by virtue of the electrochemical technique, the high-resolution transmission electron microscopy, and the in operando fuel cell–X-ray absorption spectroscopy techniques, it was revealed that Co2+Ohin CoO is the main active site, which under electrochemical conditions tends to transform into Co3+Ohand form Co3O4with a hollow structure due to the Kirkendall effect; nevertheless, it retains decent ORR activity due to the formation of the unique hollow structure.

Developing low cost, high active and stable non noble electrocatalysts for oxygen reduction reaction (ORR) is of great importance for the practical application of proton exchange membrane fuel cells (PEMFCs). Herein, we develop a hydrogel-pyrolysis strategy to synthesize an active iron/nitrogen/phosphorous co-doped carbon electrocatalyst (denoted as PANI-Fe/PA-N1050) by adopting aniline, phytic acid and iron trichloride as the precursors. The catalytic behavior for ORR in 0.1M NaOH solution was examined by cyclic voltammetry (CV), linear scanning voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results show that, compared with the single-doped counterparts, the iron/nitrogen/phosphorous co-doped carbon electrocatalyst exhibits a superior ORR performance in terms of an initial half-wave potential of 0.84 V vs. RHE and degradation of 14 mV after 1000 cycles. The performance enhancement could be attributed to the following aspects: (1) the crosslink of phytic acid and polyaniline forms a hydrogel, which after pyrolysis possesses high electrochemical surface area so that allows to accommodate quantity of active sites; (2) the Fe, N, P triple-doping generates abundant active sites including Fe-Nx, graphitic N and P-doped carbon; (3) the charge transfer resistance decreases benefiting from the continuous 3D porous structure of carbon. The iron/nitrogen/phosphorous co-doped 3D porous carbon materials prepared by the facile and scalable hydrogel-pyrolysis route is also promising for energy conversion/storage.

Exploring advanced electrocatalysts to accelerate the sluggish oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) is a promising route to alleviate the current challenges of fossil fuel exhaustion and environment pollution. Herein, a carbon-supported highly dispersed PtNi nanocatalyst (Pt0.61Ni/C) with low platinum content of 2.76 wt % was prepared simply based on galvanic replacement for a high-efficiency ORR process. It presents a mass activity of ∼5 times of the conventional Pt-based catalyst at 0.9 V (vs reversible hydrogen electrode (RHE)) and a remarkable durability and methanol tolerance. The acidic fuel cell with such cathode catalyst (Pt0.61Ni/C) presents a striking performance with maximum power density up to 1.1 W cm–2at 80 °C. Due to the extremely low platinum loading in the whole fuel cell, its Pt utilization (0.093 gPtkW–1) is the highest reported ever in H2/O2fuel cells. Such impressive performance of Pt0.61Ni/C makes the obtained Pt0.61Ni/C catalyst a very promising alternative to conventional Pt-based catalysts for their large-scale application in future.

Finding the electromagnetic (EM) counterpart of binary compact star merger, especially the binary neutron star (BNS) merger, is critically important for gravitational wave (GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope (HE) onboard Insight-HXMT (Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart (SSS17a/AT2017gfo) with very large collection area (~1000 cm2) and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity (ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy (0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints (~10‒7to 10‒6erg/cm2/s) for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.

Ion migration and electron transfer are crucial phenomena in electrochemistry and interfacial sciences, which require effective coupling and integration of separated charge pathways within medium materials. Here, in this work, we fabricated an ordered nanowire material based on hybrid polymers of polypyrrole, with electronic conductance, and perfluorosulfonic acid ionomers, with ionic conductance, via a facile one-step electrochemical route. Because of the nanoconfined effects for the different charge-transfer channels within the nanowire polymer matrix, the electronic and ionic conductivities of the hybrid polymer are surprisingly enhanced, being 26.4 and 0.096 S cm–1, respectively. Such an improvement in the formation of charge pathways also leads to an increased electrochemical capacitance through enlargement of the area of ion/electron transport boundaries, which may show great potential in the applications of supercapacitors, fuel cells, rechargeable batteries, and other electrochemical devices.

Carbon supported gold-iridium composite (AuIr/C) was synthesized by a facile one-step process and was investigated as the bifunctional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The physical properties of the AuIr/C composite were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Although the Au and Ir in the AuIr/C did not form alloy, it is clear that the introduction of Ir decreases the average Au particle size to 4.2nm compared to that in the Au/C (10.1nm). By systematical analysis on chemical state of metal surface via XPS and the electrochemical results, it was found that the Au surface for the Au/C can be activated by potential cycling from 0.12V to 1.72V, resulting in the increased surface roughness of Au, thus improving the ORR activity. By the same potential cycling, the Ir surface of the Ir/C was irreversibly oxidized, leading to degraded ORR activity but uninfluenced OER activity. For the AuIr/C, Ir protects Au against being oxidized due to the lower electronegativity of Ir. Combining the advantages of Au and Ir in catalyzing ORR and OER, the AuIr/C catalyst displays an enhanced catalytic activity to the ORR and a comparable OER activity. In the 50-cycle accelerated aging test for the ORR and OER, the AuIr/C displayed a satisfied stability, suggesting that the AuIr/C catalyst is a potential bifunctional catalyst for the oxygen electrode.

Nafion-membrane-based proton exchange fuel cells (PEMFCs) typically operate at below 100 °C. However, H3PO4-doped polybenzimidazole (PBI)-based PEMFCs can operate at 100–200 °C. This is advantageous because of accelerated reaction rates and enhanced tolerance to poisons such as CO and SO2, which can arise from reformed gas or the atmosphere. However, the strong adsorption of phosphoric anions on the Pt surface dramatically decreases the electrocatalytic activity. This study exploits the “third-body effect”, in which a small amount of organic molecules are pre-adsorbed on the Pt surface to inhibit the adsorption of phosphoric anions. Pre-adsorbate species inhibit the adsorption of phosphoric anions, but can also partially occlude active sites. Thus, the optimum pre-adsorbate coverage is studied by correlating the oxygen reduction reaction (ORR) activity of Pt with pre-adsorbate coverage on the Pt surface. The influence of the pre-adsorbate molecule length is investigated using the organic amines, butylamine, octylamine, and dodecylamine, in both 0.1 mol/L HClO4and 0.1 mol/L H3PO4. Such amines readily bond to the Pt surface. In aqueous HClO4electrolyte, the ORR activity of Pt decreases monotonically with increasing pre-adsorbate coverage. In aqueous H3PO4electrolyte, the ORR activity of Pt initially increases and then decreases with increasing pre-adsorbate coverage. The maximum ORR activity in H3PO4occurs at a pre-adsorbate coverage of around 20%. The effect of molecular length of the pre-adsorbate is negligible, but its coverage strongly affects the degree to which phosphoric anion adsorption is inhibited. Butylamine adsorbs to Pt at partial active sites, which decreases the electrochemically active surface area. Adsorbed butylamine may also modify the electronic structure of the Pt surface. The ORR activity in the phosphoric acid electrolyte remains relatively low, even when using the pre-adsorbate modified Pt/C catalysts. Further development of the catalyst and electrolyte is required before the commercialization of H3PO4-PBI-based PEMFCs can be realized.

Exploring non-precious metal catalysts for the oxygen reduction reaction (ORR) is essential for fuel cells and metal–air batteries. Herein, we report a Fe-N-C catalyst possessing a high specific surface area (1501 m2/g) and uniformly dispersed iron within a carbon matrix prepared viaa two-step pyrolysis process. The Fe-N-C catalyst exhibits excellent ORR activity in 0.1 mol/L NaOH electrolyte (onset potential, Eo= 1.08 V and half wave potential, E1/2= 0.88 V vs. reversible hydrogen electrode) and 0.1 mol/L HClO4electrolyte (Eo= 0.85 V and E1/2= 0.75 V vs. reversible hydrogen electrode). The direct methanol fuel cells employing Fe-N-C as the cathodic catalyst displayed promising performance with a maximum power density of 33 mW/cm2in alkaline media and 47 mW/cm2in acidic media. The detailed investigation on the composition–structure–performance relationship by X-ray diffraction, X-ray photoelectron spectroscopy and Mössbauer spectroscopy suggests that Fe-N4, together with graphitic-N and pyridinic-N are the active ORR components. The promising direct methanol fuel cell performance displayed by the Fe-N-C catalyst is related to the intrinsic high catalytic activity, and critically for this application, to the high methanol tolerance.

Three-dimensional nanoporous metals of highly porous structure and interconnected ligaments are attractive for electrochemical reactions. Herein, freestanding 3D nanoporous silver (np-Ag) is prepared by a facile electrochemical approach, i.e., first electro-oxidizing silver to silver halides followed by electro-reduction of the silver halides by controlling the potential applied to the electrode. The np-Ag displays 130 and 11.5 times enhancement in catalytic activity for the oxygen reduction reaction and the formaldehyde electro-oxidation reaction, respectively, relative to the flat polycrystalline silver, and even outperforms the commercial nano-Pt catalyst. Detailed experimental and theoretical studies discover that both the facilitated mass transportation in the 3D interconnected porous structures and the favored kinetics contribute to the superior electro-catalytic activity of np-Ag.

Direct seawater electrolysis to sustainable production of hydrogen fuel is attractive, given the abundant seawater resource on Earth. Nevertheless, current seawater electrolysis systems necessarily require external power grid to drive the electrolysis process, which are neither able to achieve continuous hydrogen production nor applicable to mobile and undersea apparatuses. Herein, we demonstrate a self-powered, direct seawater electrolysis system driven by Mg/seawater batteries for continuous hydrogen production. For a case study, a heterostructured MoNi/NiMoO4is prepared to catalyze the hydrogen evolution reaction (HER) at the cathodes of both the Mg/seawater battery and the seawater electrolysis, displaying a superior performance surpassing a commercial Pt/C with the overpotential as low as 256 mV at 10 mA cm−2in seawater. The Mg/seawater battery achieves a peak power density of 21.08 mW cm−2, serving as a power source to drive seawater electrolysis. The self-powered system yields a total hydrogen evolution rate of 12.11 mL cm−2h−1and conversion efficiency of Mg-to-hydrogen up to 83.97%. Such a self-powered direct seawater electrolysis system provides an intriguing strategy for the continuous acquisition of hydrogen fuel from infinite seawater without any external power grids.

Two-dimensional materials based on ternary system of B, C and N are useful ranging from electric devices to catalysis. The bonding arrangement within these BCN nanosheets largely determines their electronic structure and thus chemical and (or) physical properties, yet it remains a challenge to manipulate their bond structures in a convenient and controlled manner. Recently, we developed a synthetic protocol for the synthesis of crumpled BCN nanosheets with tunable B and N bond structure using urea, boric acid and polyethylene glycol (PEG) as precursors. By carefully selecting the synthesis condition, we can tune the structure of BCN sheets from s-BCN with B and N bond together to h-BCN with B and N homogenously dispersed in BCN sheets. Detailed experiments suggest that the final bond structure of B and N in graphene depends on the preferentially doped N structure in BCN nanosheets. When N substituted the in-plane carbon atom with all its electrons configured into the π electron system of graphene, it facilitates the formation of h-BCN with B and N in separated state. On the contrary, when nitrogen substituted the edge-plane carbon with the nitrogen dopant surrounded with the lone electron pairs, it benefits for the formation of B–N structure. Specially, the compound riched with h-BCN shows excellent ORR performance in alkaline solution due to the synergistic effect between B and N, while s-BCN dominant BCN shows graphite-like activity for ORR, suggesting the intrinsic properties differences of BCN nanosheets with different dopants bond arrangement.

Carbon supported Pt–Ni nanoparticles (NPs) electrocatalysts with nominal Pt/Ni atomic ratios of 3:1, 2:1, and 1:1, denoted as Pt3Ni/C, Pt2Ni/C, and Pt1Ni/C, respectively, were obtained by a modified polyol process. The structure of PtnNi/C (n= 3, 2, 1) electrocatalysts was studied by using an X-ray absorption spectroscopy technique combined with X-ray diffraction and transmission electron microscopy. Significantly, the NPs of Pt3Ni/C in air are demonstrated to have a quasi core–shell structure consisting of a core of metallic Pt surrounded by many small NiOxclusters. In contrast, both Pt2Ni/C and Pt1Ni/C are demonstrated to have an alloy structure with partial oxidation on the surface. Under the atmosphere of H2at 393 K, the PtnNi/C became the expected bimetallic alloy. At last, we discuss the effect of Ni amount on the structure of PtnNi/C and estimate their possible catalytic activity for methanol oxidation reaction. Our results further confirmed that the structure of Pt–Ni NPs can be influenced by Ni amount and this effect may be enlarged by environment effects.

Highly ordered polypyrrole nanowire arrays are constructed viaelectrochemically polymerizing pyrrole directly on Pd-modified Nafion® membrane. A significant enhancement in the performance and durability of direct methanol fuel cells (DMFCs) is observed when such an ordered structure is used as an ordered electrode.

Carbon-supported bimetallic PtmNinelectrocatalysts with different Pt/Ni atomic ratios were synthesized through a modified polyol process. The as-prepared electrocatalysts were characterized by X-ray diffraction, transmission electron microscopy, voltammetry techniques, and single-cell tests. It was revealed that the PtmNinbimetallic nanoparticles were uniformly distributed on carbon supports with average diameters of about 3 nm. Pt and Ni were partially alloyed, indicated by the decreased Pt lattice constants compared with that of pure Pt. The results of the electrochemical measurements showed that the PtmNin/C catalysts, compared with the Pt/C, have superior specific activity toward the methanol electrooxidation reaction (MOR) in alkaline media as well as a higher power density in a direct methanol fuel cell test with the Pt3Ni1/C as the anode catalyst. Density functional theory studies further revealed that the electronic structure of Pt was modified by Ni due to the charge transfer from Ni to Pt atoms in PtmNinclusters, leading to a weakened CO adsorption on PtmNinbinary clusters than on Pt itself. This provides an explanation for the enhanced MOR activity of the PtmNin/C catalysts.

Two carbon-supported molybdenum nitrides, MoN/C and Mo2N/C, were prepared by varying the experimental conditions in NH3atmosphere. The physical properties of the catalysts were characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The catalytic activities of the catalysts toward the oxygen reduction reaction (ORR) and the methanol oxidation reaction (MOR) were characterized by potentiodynamic measurements. The results show that the MoN/C exhibits higher catalytic activity toward the ORR than the Mo2N/C. Both catalysts are inert to methanol. The results from the density functional theory calculation indicate that both the MoN and the Mo2N facilitate dissociation of oxygen molecules. The suitable geometric structure of the MoN and the preferred oxygen adsorption type on it contribute to the higher activity of the MoN/C toward the ORR. The calculation results agree well with the results from the experiments.

Herein, a unique carbon sponge FeNC@GA-MF with a hierarchical porous structure was prepared by a multi-step self-assembly strategy, with a high surface area of 1184.8 m2g–1, a pseudocapacitance of 133.5 F g–1, and also superior activity for the oxygen reduction reaction (E1/2= 0.866 VRHE). The Zn–air battery fabricated with the FeNC@GA-MF cathode delivers a peak power density of 156 mW cm–2and a satisfied stability, outperforming the Pt/C cathode, benefiting from the high intrinsic activity and large surface area of the unique hierarchical porous structure. This work provides an effective strategy to fabricate self-supporting electrodes for fuel cells and supercapacitors.

An improved aqueous impregnation method was used to prepare 40 wt PtC electrocatalysts. TEM analysis of the samples showed that the Pt particles impregnated for a short time have a very narrow size distribution in the range of 1–4 nm with an average size of 2.6 nm. UV-vis spectroscopy measurements verified that the redox reaction between PtCl62−and formaldehyde took place with a slow rate at ambient temperature viaa two-step reaction path, where PtCl42−serves as an intermediate. The use of the short-time-impregnated 40 wt PtC as cathode electrocatalysts in direct methanol fuel cells yields better performance than that of commercial 40 wt PtC electrocatalyst. Experimental evidence provides clues for the fundamental understanding of elementary steps of the redox reactions, which helps in guiding the design and preparation of highly dispersed Pt catalyst for fuel cells.

An improved aqueous impregnation method was used to prepare 40 wt% Pt/C electrocatalysts. TEM analysis of the samples showed that the Pt particles impregnated for a short time have a very narrow size distribution in the range of 1–4 nm with an average size of 2.6 nm. UV-vis spectroscopy measurements verified that the redox reaction between PtCl₆2− and formaldehyde took place with a slow rate at ambient temperature via a two-step reaction path, where PtCl₄2− serves as an intermediate. The use of the short-time-impregnated 40 wt% Pt/C as cathode electrocatalysts in direct methanol fuel cells yields better performance than that of commercial 40 wt% Pt/C electrocatalyst. Experimental evidence provides clues for the fundamental understanding of elementary steps of the redox reactions, which helps in guiding the design and preparation of highly dispersed Pt catalyst for fuel cells.

Alcohol electrooxidation reaction (AOR) is of sluggish kinetics, which as the anodic reaction of direct alcohol fuel cells determines largely the discharging performance of the device. Solar energy as an endless energy source is introduced to promote the AOR kinetics. Herein, the recent progress on photo‐promoted AOR and the application in fuel cells is reviewed, including 1) design of the AOR photoelectrocatalysts, 2) photoelectrocatalysis mechanism, and 3) fabrication of photo‐promoted direct alcohol fuel cells (PDAFCs). Finally, a perspective on the challenges of PDAFCs and new directions in this exciting and still emerging research area are given. The recent developments of photo‐promoted alcohol electrooxidation for the application in fuel cells are reviewed, including the design of the photoelectrocatalysts for alcohol oxidation, mechanism study, and the practical device application. Finally, a summary is given and some perspectives are provided on the challenges and new directions in this exciting and still emerging area of research.

Judiciously engineering the electrocatalysts is attractive and challenging to exploit materials with high electrocatalytic performance for hydrogen evolution reaction. Herein, we successfully perform the interface engineering by alternately depositing Co–P and Ni–Fe–P films on nickel foam, via facile electroless plating and de-alloying process. This work shows that there is a significant effect of de-alloying process on alloy growth. The electronic structure of layered alloys is improved by interface engineering. The multilayer strategy significantly promotes the charge transfer. Importantly, the Co–P/Ni–Fe–P/NF electrode fabricated by interface engineering exhibits excellent electrocatalytic hydrogen evolution activity with an overpotential of 43.4 mV at 10 mA cm−2and long-term durability for 72 h in alkaline medium (1 M KOH). The innovative strategy of this work may aid further development of commercial electrocatalysts.

A facile method to prepare Fe–N–C catalysts with a 3D porous structure is reported, where melamine foam is used as the self‐sacrificed template, and citric acid (CA) and iron salts are used as the precursors. The morphology and chemical valence state of the surface elements of the catalyst are characterized. Cyclic voltammetry (CV), liner scanning voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) are used to evaluate the catalytic performance on the oxygen reduction reaction (ORR). The catalyst CA‐Fe/MF‐N900 (calcinated at 900 °C) exhibits the best ORR performance. In alkaline electrolyte, the ORR current starts at 0.98 V versus reversible hydrogen electrode (RHE). The half‐wave potential (E1/2) is 0.83 V versus RHE, and the limiting current density reaches 5.3 mA cm−2. After 1000 cycles, E1/2merely shifts negatively by 7 mV. The Zn–air battery fabricated with the CA‐Fe/MF‐N900 as the cathode catalyst displays outstanding discharging performance with peak power density of 158 mW cm−2and long‐term stability. The enhanced catalytic activity can be attributed to the advanced 3D interconnected porous architecture of the Fe–N–C catalyst, which can not only accommodate abundant active sites but also significantly reduce the mass/charge transfer resistance. A new 3D porous Fe–N–C composite is constructed, where melamine foam is used as the self‐scarified template, and citric acid (CA) and iron salts are used as the precursors. The Zn–air battery fabricated with CA‐Fe/MF‐N900 as the cathode catalyst displays outstanding discharging performance with peak power density of 158 mW cm−2and long‐term stability.

As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was designed to perform pointing, scanning and gamma-ray burst (GRB) observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed. Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.

Developing low cost, high active and stable non noble electrocatalysts for oxygen reduction reaction (ORR) is of great importance for the practical application of proton exchange membrane fuel cells (PEMFCs). Herein, we develop a hydrogel-pyrolysis strategy to synthesize an active iron/nitrogen/phosphorous co-doped carbon electrocatalyst (denoted as PANI-Fe/PA-N1050) by adopting aniline, phytic acid and iron trichloride as the precursors. The catalytic behavior for ORR in 0.1M NaOH solution was examined by cyclic voltammetry (CV), linear scanning voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results show that, compared with the single-doped counterparts, the iron/nitrogen/phosphorous co-doped carbon electrocatalyst exhibits a superior ORR performance in terms of an initial half-wave potential of 0.84 V vs. RHE and degradation of 14 mV after 1000 cycles. The performance enhancement could be attributed to the following aspects: (1) the crosslink of phytic acid and polyaniline forms a hydrogel, which after pyrolysis possesses high electrochemical surface area so that allows to accommodate quantity of active sites; (2) the Fe, N, P triple-doping generates abundant active sites including Fe-Nx, graphitic N and P-doped carbon; (3) the charge transfer resistance decreases benefiting from the continuous 3D porous structure of carbon. The iron/nitrogen/phosphorous co-doped 3D porous carbon materials prepared by the facile and scalable hydrogel-pyrolysis route is also promising for energy conversion/storage.

A novel carbon-supported palladium-rich Pd3Pt1C catalyst prepared by a modified polyol process showed a better cell performance than PtC in direct methanol fuel cells, which may be attributed to palladium's inactivity to methanol electro-oxidation while exhibiting good performance to oxygen reduction reaction.

A 40 wt% Pt/C cathode electrocatalyst with controlled Pt particle size of ~2.9 nm showing better performance than commercial catalyst for direct methanol fuel cell was prepared by a polyol process with water but without using stabilizing agent.

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