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Cost-efficient electrocatalysts composed of earth-abundant elements are highly desired for enhanced oxygen evolution reaction (OER). As a promising candidate, metallic Co4N already demonstrated electrocatalytic performance relying on specific nanostructures and electronic configurations. Herein, nickel was introduced as the dopant into one-dimensional (1D) hierarchical Co4N structures, achieving effective electronic regulation of Co4N toward high OER performance. The amount of Co3+increased after Ni-doping, and the in-situformed surface oxyhydroxide during OER enhanced the electrocatalytic kinetics. Meanwhile, the 1D hierarchical structure further promoted the performances of Co4N owing to the high electrical conductivity and abundant active-sites on the rough surface. As expected, the optimal Ni-doped Co4N with a Ni/Co molar ratio of 0.25 provides a small overpotential of 233 mV at a current density of 10 mAcm−2, with a low Tafel slope of 61 mV dec−1, and high long-term stability in 1.0 mol L−1KOH. Following these results, the enhancement by doping the Co4N nanowire bundles with Fe and Cu was further evidenced for the OER.

Precisely tailoring the location and strength of Brønsted acid is crucial for the catalytic cracking of polyolefins. Here, by simple sodium cation exchange (xNa-USY, where xis the Na/Al ratio), it was unexpectedly discovered that xNa-USY (x < 0.5) displayed a lower cracking temperature of polypropylene (PP) with optimum performance and excellent reproducibility at x = 0.38, rather than pure H-USY, as generally believed. Combining spectroscopic and microstructural characterizations, a putative mechanism was proposed from the perspective of proton location and acid strength. When lacking strong Brønsted acid near site II, PP tended to cleave into longer alkane fractions at low temperatures and volatilized directly, exhibiting significant apparent cracking capacity. Meanwhile, the lower distribution of olefins and aromatics remarkably reduced coke generation at high temperatures. These findings not only shed light on the optimization of plastic degradation catalysts but also expand our knowledge of the zeolitic acid-catalyzed cracking process.

It is highly desired to directly use commercial nickel foam (CNF) as an electrocatalyst for the oxygen evolution reaction (OER) via simple surface reconstruction. In our research, a simple three-step preactivation process was proposed to reconstruct CNF as an efficient OER catalyst, including calcination, high-voltage treatment, and immersing in electrolyte. The optimal CNF after three-step activation reaches an excellent OER performance of 228 and 267 mV at η10and η100in alkaline media and can tolerate long-term tests under a large current density of 500 mA·cm–2. The promotion of each step was explored. The calcination step leads to a reconstructive surficial morphology with an enlarged active surface, providing a prerequisite for the following construction steps. The high-voltage treatment changes the valence of surface Ni species, generating phases with higher catalytic activity, and the immersing process introduces Fe heteroatoms into the surface of CNF, boosting the catalytic performance of CNF through Ni–Fe interactions. This research provides a simple method of making high-performance catalysts with accessible nickel foam, a potential for large-scale application in practical industry, and new thinking for the manipulation of Ni-based catalysts.

Chinese handmade papers have been the carriers of paper-based documents, paintings and calligraphies, which are of great importance for historical and cultural heritage studies. This research developed the attenuated total reflectance-Fourier transform infrared(ATR-FTIR) spectroscopic technique for the analysis of Chinese handmade papers. The test was applied to Chinese handmade papers taken from bark, hemp and bamboo groups, followed by papers from ancient books and arts collected in library and museum. Our study indicated that FTIR was an efficient analytical method to identify fiber types of library/museum papers of unknown origin. Moreover, information about degree of crystallinity and state of deterioration of cellulosic fibers was learned from FTIR spectra. This research provides a non-destructive method to study the molecular structure of cellulosic fibers, and guides the selection of appropriate Chinese handmade papers for the restoration of cultural heritage objects.

Dicarboxylic acids and cyclic ketones, such as adipic acid (AA) and cyclohexanone (CHN), are essential compounds for the chemical industry. Although their production by electrosynthesis using electricity is considered one of the most promising strategies, the application of such processes has been hampered by a lack of efficient catalysts as well as a lack of understanding of the mechanism. Herein, a series of monolithic msig/ea-NiOOH-Ni(OH)2/NF were prepared by means of self-dissolution of metal matrix components, interface growth, and electrochemical activation (denoted as msig/ea). The as-synthesized catalysts have three-dimensional cuboid-like structures formed by interconnecting nanosheets composed of NiOOH. By theoretically guided regulation of the amounts of Ni3+and oxygen vacancies (OV), a 96.5% yield of CHN from cyclohexanol (CHA) dehydrogenation and a 93.6% yield of AA from CHN oxidation were achieved. A combined experimental and theoretical study demonstrates that CHA dehydrogenation and CHN oxidation were promoted by the formation of Ni3+and the peroxide species (*OOH) on OV. This work provides a promising approach for directional electrosynthesis of high-purity chemicals with in-depth mechanistic insights.

Transition metal carbides (TMCs) are regarded as cost-efficient and stable electrocatalysts for hydrogen evolution reaction (HER). Nitrogen doping into nanosized TMCs in a control manner (e.g., doping amount and site) is one of the most effective routes to intrinsically enhance activity and durability owing to the ameliorated Mo-H strength and amplified active sites. Herein, an approach based on reticular chemistry is developed to synthesize nanosized N-doped Mo2C embedded in porous carbon (N-Mo2C/PC), via pyrolyzing a hybrid precursor consisting of highly-dispersed molybdates within melamine-benzenetricarboxylic acid supermolecule networks. With optimal N-doping, the N-Mo2C/PC electrocatalyst exhibits excellent HER stability and activity with overpotential of 109 mV at 10 mA cm-2in 0.5 M H2SO4, as well as 100 mV at 10 mA cm-2in 1.0 M KOH. Density functional theory (DFT) calculations confirm that the appropriate N doping on the surface of Mo2C nanoparticles would accelerate the HER process via weakening the Mo–H bond strength and lowering H-H coupling barrier. Furthermore, Mo2C nanoparticles loaded on carbon cloth with high HER activity can also be successfully achieved by this strategy. This work paves a universal way to design active sites-enriched TMCs with high performance in energy conversion and storages.