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Large-scale industrial application of electrolytic splitting of water has called for the development of oxygen evolution electrodes that are inexpensive, robust and can deliver large current density (>500 mA cm −2 ) at low applied potentials. Here we show that an efficient oxygen electrode can be developed by electrodepositing amorphous mesoporous nickel–iron composite nanosheets directly onto macroporous nickel foam substrates. The as-prepared oxygen electrode exhibits high catalytic activity towards water oxidation in alkaline solutions, which only requires an overpotential of 200 mV to initiate the reaction, and is capable of delivering current densities of 500 and 1,000 mA cm −2 at overpotentials of 240 and 270 mV, respectively. The electrode also shows prolonged stability against bulk water electrolysis at large current. Collectively, the as-prepared three-dimensional structured electrode is the most efficient oxygen evolution electrode in alkaline electrolytes reported to the best of our knowledge, and can potentially be applied for industrial scale water electrolysis. Development of efficient and affordable oxygen evolution catalysts is essential for large-scale electrolytic water splitting. Here, the authors report mesoporous nickel–iron composite nanosheets loaded on macroporous nickel foam substrates, and evaluate their electrocatalytic oxygen evolution in basic media.

Two-dimensional metal-organic frameworks represent a family of materials with attractive chemical and structural properties, which are usually prepared in the form of bulk powders. Here we show a generic approach to fabricate ultrathin nanosheet array of metal-organic frameworks on different substrates through a dissolution–crystallization mechanism. These materials exhibit intriguing properties for electrocatalysis including highly exposed active molecular metal sites owning to ultra-small thickness of nanosheets, improved electrical conductivity and a combination of hierarchical porosity. We fabricate a nickel-iron-based metal-organic framework array, which demonstrates superior electrocatalytic performance towards oxygen evolution reaction with a small overpotential of 240 mV at 10 mA cm −2 , and robust operation for 20,000 s with no detectable activity decay. Remarkably, the turnover frequency of the electrode is 3.8 s −1 at an overpotential of 400 mV. We further demonstrate the promise of these electrodes for other important catalytic reactions including hydrogen evolution reaction and overall water splitting. Metal-organic frameworks are generally considered to be inert catalysts for many electrochemical reactions, however this is not always the case. Here the authors fabricate an ultrathin nanosheet array of metal-organic frameworks exhibiting enhanced performance toward electrocatalytic water splitting.

Background To evaluate the global burden of cataracts by year, age, region, gender, and socioeconomic status using disability-adjusted life years (DALYs) and prevalence from the Global Burden of Disease (GBD) study 2019. Methods Global, regional, or national DALY numbers, crude DALY rates, and age-standardized DALY rates caused by cataracts, by year, age, and gender, were obtained from the Global Burden of Disease Study 2019. Socio-demographic Index (SDI) as a comprehensive indicator of the national or regional development status of GBD countries in 2019 was obtained from the GBD official website. Kruskal-Wallis test, linear regression, and Pearson correlation analysis were performed to explore the associations between the health burden with socioeconomic levels, Wilcoxon Signed-Rank Test was used to investigate the gender disparity. Results From 1990 to 2019, global DALY numbers caused by cataracts rose by 91.2%, crude rates increased by 32.2%, while age-standardized rates fell by 11.0%. Globally, age-standardized prevalence and DALYs rates of cataracts peaked in 2017 and 2000, with the prevalence rate of 1283.53 [95% uncertainty interval (UI) 1134.46–1442.93] and DALYs rate of 94.52 (95% UI 67.09–127.24) per 100,000 population, respectively. The burden was expected to decrease to 1232.33 (95% UI 942.33–1522.33) and 91.52 (95% UI 87.11–95.94) by 2050. Southeast Asia had the highest blindness rate caused by cataracts in terms of age-standardized DALY rates (99.87, 95% UI: 67.18–144.25) in 2019. Gender disparity has existed since 1990, with the female being more heavily impacted. This pattern remained with aging among different stages of vision impairments and varied through GBD super regions. Gender difference (females minus males) of age-standardized DALYs (equation: Y = -53.2*X + 50.0,  P  < 0.001) and prevalence rates (equation: Y = − 492.8*X + 521.6,  P  < 0.001) was negatively correlated with SDI in linear regression. Conclusion The global health of cataracts is improving but the steady growth in crude DALY rates suggested that health progress does not mean fewer demands for cataracts. Globally, older age, females, and lower socioeconomic status are associated with higher cataract burden. The findings of this study highlight the importance to make gender-sensitive health policies to manage global vision loss caused by cataracts, especially in low SDI regions.

Aromatic tertiary amines are one of the most important classes of organic compounds in organic chemistry and drug discovery. It is difficult to efficiently construct tertiary amines from primary amines via classical nucleophilic substitution due to consecutive overalkylation. In this paper, we have developed a radical tandem C-N coupling strategy to efficiently construct aromatic tertiary amines from commercially available carboxylic acids and nitroarenes. A variety of aromatic tertiary amines can be furnished in good yields (up to 98%) with excellent functional group compatibility under mild reaction conditions. The use of two different carboxylic acids also allows for the concise synthesis of nonsymmetric aromatic tertiary amines in satisfactory yields. Mechanistic studies suggest the intermediacy of the arylamine–(TPP)Fe(III) species and might provide a possible evidence for an S H 2 (bimolecular homolytic substitution) pathway in the critical C-N bond formation step. Aromatic tertiary amines are versatile building blocks in organic synthesis. In this article, the authors report on an iron-catalysed reaction for the decarboxylative C-N coupling from carboxylic acids and nitroarenes, leading to non-symmetric tertiary aromatic amines.

Lifting the valley degeneracy of monolayer transition metal dichalcogenides (TMDs) would allow versatile control of the valley degree of freedom. We report a giant valley exciton splitting of 16 meV/T for monolayer WS 2 , using the proximity effect from an EuS substrate, which is enhanced by nearly two orders of magnitude from that obtained by an external magnetic field. More interestingly, a sign reversal of the valley splitting is observed as compared to that of WSe 2 on EuS. Using first principles calculations, we investigate the complex behavior of exchange interactions between TMDs and EuS. The sign reversal is attributed to competing ferromagnetic (FM) and antiferromagnetic (AFM) exchange interactions for Eu- and S- terminated EuS surface sites. They act differently on the conduction and valence bands of WS 2 compared to WSe 2 . Tuning the sign and magnitude of the valley exciton splitting offers opportunities for control of valley pseudospin for quantum information processing. Valley degree of freedom promises the additional control of electrons in 2D materials but is limited by small valley splitting. Here the authors show heavily enhanced valley splitting in monolayer WS 2 on EuS substrate due to competing ferromagnetic and antiferromagnetic exchange interactions for Eu- and S-terminated EuS surface sites.

Efficient generation of hydrogen from water-splitting is an underpinning chemistry to realize the hydrogen economy. Low cost, transition metals such as nickel and iron-based oxides/hydroxides have been regarded as promising catalysts for the oxygen evolution reaction in alkaline media with overpotentials as low as ~200 mV to achieve 10 mA cm −2 , however, they are generally unsuitable for the hydrogen evolution reaction. Herein, we show a Janus nanoparticle catalyst with a nickel–iron oxide interface and multi-site functionality for a highly efficient hydrogen evolution reaction with a comparable performance to the benchmark platinum on carbon catalyst. Density functional theory calculations reveal that the hydrogen evolution reaction catalytic activity of the nanoparticle is induced by the strong electronic coupling effect between the iron oxide and the nickel at the interface. Remarkably, the catalyst also exhibits extraordinary oxygen evolution reaction activity, enabling an active and stable bi-functional catalyst for whole cell water-splitting with, to the best of our knowledge, the highest energy efficiency (83.7%) reported to date. Ni–Fe based compound are known as active electrocatalysts for oxygen evolution reaction, but not a good choice for the other half-reaction of water-splitting. Here the authors report a unique interface between Ni and γ-Fe 2 O 3 that efficiently catalyzes the cathodic hydrogen evolution reaction.

Electrocatalytic synergy is a functional yet underrated concept in electrocatalysis. Often, it materializes as intermetallic interaction between different metals. We demonstrate interphasic synergy in monometallic structures is as much effective. An interphasic synergy between Ni(OH) 2 and Ni-N/Ni-C phases is reported for alkaline hydrogen evolution reaction that lowers the energy barriers for hydrogen adsorption-desorption and facilitates that of hydroxyl intermediates. This makes ready-to-serve Ni active sites and allocates a large amount of Ni d -states at Fermi level to promote charge redistribution from Ni(OH) 2 to Ni-N/Ni-C and the co-adsorption of H ads and OH ads intermediates on Ni-N/Ni-C moieties. As a result, a Ni(OH) 2 @Ni-N/Ni-C hetero-hierarchical nanostructure is developed, lowering the overpotentials to deliver −10 and −100 mA cm −2 in alkaline media by 102 and 113 mV, respectively, compared to monophasic Ni(OH) 2 catalyst. This study unveils the interphasic synergy as an effective strategy to design monometallic electrocatalysts for water splitting and other energy applications. Electrocatalytic synergy is a functional yet underrated concept in electrocatalysis. Here the authors disclose interphasic synergy between Ni(OH)2 and Ni-N/Ni-C phases for hydrogen evolution reaction in alkaline media.

Active and stable electrocatalysts are essential for hydrogen production from alkaline water electrolysis. However, precisely controlling the interaction between electrocatalysts and reaction intermediates (H 2 O*, H*, and *OH) remains challenging. Here, we demonstrate an yttrium-doped NiMo-MoO 2 heterogenous electrocatalyst that efficiently promotes water dissociation and accelerates the intermediate adsorption/desorption dynamics in alkaline electrolytes. Introducing yttrium into the NiMo/MoO 2 heterostructure induces lattice expansion and optimizes the d -band center of NiMo alloy component, enhancing water dissociation and H* desorption. Yttrium doping also increases the concentration of oxygen vacancies in MoO 2−x , which in turn accelerates the charge kinetics and the swift evacuation of *OH intermediates from the active sites. Consequently, the Y-NiMo/MoO 2−x heterostructure exhibits notable performance by requiring only 189 and 220 mV overpotentials to achieve current density of 2.0 A cm −2 in alkaline water and seawater, respectively. This work provides a strategy to modulate heterostructure catalysts for scalable, economically viable hydrogen production from low-quality waters. Hydrogen production from alkaline seawater requires efficient catalysts, but controlling interaction with intermediates is challenging. Here, the authors report an yttrium-doped NiMo-MoO2 catalyst that optimizes water dissociation and enables efficient seawater splitting at high current densities.

HighlightsThe electrode–electrolyte interface reactions (complete desolvation process and incomplete process), interphase design strategies, and advanced interphase analysis techniques for aqueous proton batteries are discussed and reviewed.Research progresses on pure phase aqueous electrolytes, hybrid aqueous electrolytes, non-aqueous electrolytes, and solid/quasi-solid electrolytes are summarized.Perspectives on both interphase and electrolytes are discussed which can direct researchers to rationally design new interphase and electrolytes for high-performance proton batteries in the future.Rechargeable proton batteries have been regarded as a promising technology for next-generation energy storage devices, due to the smallest size, lightest weight, ultrafast diffusion kinetics and negligible cost of proton as charge carriers. Nevertheless, a proton battery possessing both high energy and power density is yet achieved. In addition, poor cycling stability is another major challenge making the lifespan of proton batteries unsatisfactory. These issues have motivated extensive research into electrode materials. Nonetheless, the design of electrode–electrolyte interphase and electrolytes is underdeveloped for solving the challenges. In this review, we summarize the development of interphase and electrolytes for proton batteries and elaborate on their importance in enhancing the energy density, power density and battery lifespan. The fundamental understanding of interphase is reviewed with respect to the desolvation process, interfacial reaction kinetics, solvent-electrode interactions, and analysis techniques. We categorize the currently used electrolytes according to their physicochemical properties and analyze their electrochemical potential window, solvent (e.g., water) activities, ionic conductivity, thermal stability, and safety. Finally, we offer our views on the challenges and opportunities toward the future research for both interphase and electrolytes for achieving high-performance proton batteries for energy storage.

China has set a goal to achieve peak CO 2 emissions before 2030 and carbon neutrality by 2060. To achieve the goals of carbon peak and carbon neutrality, China needs to address the challenge of the large and still growing CO 2 emission base. This paper investigated the energy consumption and CO 2 emission in Beijing from 2020–2035 based on the energy elasticity coefficient and contribution value of the sub-energy increment (CVSI) method. Beijing is one of the first cities in China to propose the \"carbon peak” target as of 2020. From 2020 Beijing will strive to achieve the goal of carbon neutrality. The results show that in 2035 the CO 2 emission in Beijing may drop to 50% of 2020. This decline would be affected by economic growth, energy efficiency and the proportion of renewable energy use. Beijing’s energy supply mainly comes from outside the region. Therefore, for Beijing, in addition to increasing the proportion of renewable energy sources outside the region, its own energy acceptance also needs to be strengthened, including strengthening energy storage construction, actively researching and promoting carbon capture and utilization of gas-fired units, which are effective ways to achieve carbon neutrality target.