The exploration of earth‐abundant and high‐efficiency electrocatalysts for the oxygen evolution reaction (OER) is of great significant for sustainable energy conversion and storage applications. Although spinel‐type binary transition metal oxides (AB2O4, A, B = metal) represent a class of promising candidates for water oxidation catalysis, their intrinsically inferior electrical conductivity exert remarkably negative impacts on their electrochemical performances. Herein, we demonstrates a feasible electrospinning approach to concurrently synthesize CoFe2O4 nanoparticles homogeneously embedded in 1D N‐doped carbon nanofibers (denoted as CoFe2O4@N‐CNFs). By integrating the catalytically active CoFe2O4 nanoparticles with the N‐doped carbon nanofibers, the as‐synthesized CoFe2O4@N‐CNF nanohybrid manifests superior OER performance with a low overpotential, a large current density, a small Tafel slope, and long‐term durability in alkaline solution, outperforming the single component counterparts (pure CoFe2O4 and N‐doped carbon nanofibers) and the commercial RuO2 catalyst. Impressively, the overpotential of CoFe2O4@N‐CNFs at the current density of 30.0 mA cm−2 negatively shifts 186 mV as compared with the commercial RuO2 catalyst and the current density of the CoFe2O4@N‐CNFs at 1.8 V is almost 3.4 times of that on RuO2 benchmark. The present work would open a new avenue for the exploration of cost‐effective and efficient OER electrocatalysts to substitute noble metals for various renewable energy conversion/storage applications.

The gut microbiota, including probiotics and pathogenic microorganisms, is involved in ulcerative colitis (UC) by regulating pathogenic microorganisms and the production of intestinal mucosal antibodies. Huangqin decoction (HQD), a traditional Chinese formula chronicled in the Shanghan lun, has been recognized as an effective drug for UC, owing to its anti-inflammatory and anti-oxidative properties. In the present study, we investigated whether HQD ameliorates dextran sulphate sodium (DSS)-induced colitis through alteration of the gut microbiota. We found that HQD significantly inhibited colitis, alleviating the loss of body weight, disease activity index, colon shortening, tissue injury, and inflammatory cytokine changes induced by DSS treatment. Principal component analysis and principal co-ordinate analysis showed an obvious difference among the groups, with increased diversity in the DSS and DSS+HQD groups. Linear discriminant analysis effect size was used to determine differences between the groups. The relative abundance of Lactococcus was higher in the DSS+HQD group than in the DSS group, whereas Desulfovibrio and Helicobacter were decreased. Furthermore, the protective effect of HQD was attenuated only in antibiotic-treated mice. In conclusion, our results suggest that HQD could ameliorate DSS-induced inflammation through alteration of the gut microbiota.

To reveal the role of oxygen vacancies in the solar water oxidation of α-Fe 2 O 3 photoanodes, the kinetic and thermodynamic properties that are closely related to the water oxidation reaction of the α-Fe 2 O 3 photoanode containing oxygen vacancies were investigated. Compared with the pristine α-Fe 2 O 3 photoanode, the presence of surface oxygen vacancies can improve the water oxidation activity and stability of the α-Fe 2 O 3 photoanode simultaneously, but the bulk oxygen vacancies have a negative effect on the water oxidation performance of the α-Fe 2 O 3 photoanode. In thermodynamics, our investigations revealed that the presence of surface oxygen vacancies narrows the space charge region width of the α-Fe 2 O 3 photoanode, which could boost the charge separation and transfer efficiency of the α-Fe 2 O 3 photoanode during water oxidation. Because the surface property and hydrophilicity of α-Fe 2 O 3 are modified owing to the presence of surface oxygen vacancies, the water oxidation kinetics of the α-Fe 2 O 3 photoanode with surface oxygen vacancies is obviously boosted. Our findings in the present work provide comprehensive understanding of the thermodynamic and kinetic differences for α-Fe 2 O 3 photoanodes with and without oxygen vacancies for solar water oxidation.

A novel magnesium phosphate-based gel (TMP-BG) with excellent printability was developed for application in 3D printing.

The manipulation of photoelectrodes' electron− hole pairs toward low recombination is the fundamental strategy to achieve high solar-to-hydrogen conversion efficiency in photoelectrochemical (PEC) water splitting cells. Herein, we demonstrate that a magnet placed parallel to a photoelectrode can improve the water splitting activity of typical BiVO 4 and α-Fe 2 O 3 photoanodes as well as Cu 2 O/CuO and p-Si(111) photocathodes by restraining the nonradiative recombination of their carrier. Our investigations indicate that magnetic field-assisted PEC water splitting is a more effective approach than the conventional PEC water splitting. Magnetic field assistance provides a new, effective, and general strategy to improve the activity of photoelectrodes for solar water splitting and the other PEC reactions.

Combining the self-sacrifice of a highly crystalline substance to design a multistep chain reaction towards ultrathin active-layer construction for high-performance water splitting with atmospheric-temperature conditions and an environmentally benign aqueous environment is extremely intriguing and full of challenges. Here, taking cobalt carbonate hydroxides (CCHs) as the initial crystalline material, we choose the Lewis acid metal salt of Fe(NO 3 ) 3 to induce an aqueous-phase chain reaction generating free CO 3 2À ions with subsequent instant FeCO 3 hydrolysis. The resultant ultrathin (~5 nm) amorphous Fe-based hydroxide layer on CCH results in considerable activity in catalyzing the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), yielding 10/50 mA • cm À 2 at overpotentials of 230/266.5 mV for OER and 72.5/197.5 mV for HER. The catalysts can operate constantly in 1.0 M KOH over 48 and 45 h for the OER and HER, respectively. For bifunctional catalysis for alkaline electrolyzer assembly, a cell voltage as low as 1.53 V was necessary to yield 10 mA cm À 2 (1.7 V at 50 mA cm À 2 ). This work rationally builds high-efficiency electrochemical bifunctional water-splitting catalysts and offers a trial in establishing a controllable nanolevel ultrathin lattice disorder layer through an atmospheric-temperature chemical route.

No abstract

Acidophilic highly-photoluminescent ionic liquid (IL)-modified carbon dots (CDs) were fabricated directly from polyethylene glycol-2000 (PEG 2000N ) by a simple one-step hydrothermal method in a system containing an IL (1-butyl-3-methylimidazolium bromide [C 4 mim]Br) and hydrochloric acid (HCl). In this process, PEG 2000N works as the carbon source, [C 4 mim]Br as the modifier, and HCl as the accelerator. CDs with low photoluminescence (PL) intensity and quantum yields (QYs) were generated in the system without H + , but CDs with high PL intensity and QYs could be prepared after H + was introduced. Moreover, with the increase of H + concentration, the QYs of the prepared CDs increase subsequently, and the highest QY reaches up to 43%. The formation mechanism was explored, and the results showed that H + changes the surface groups of the CDs generated without H + into those that exist on the CDs generated with H + , which further improves the PL performance of the CDs. Different from most CDs reported in the literature, the as-prepared CDs can still exhibit high PL intensity even under strong acidic condition.