No abstract

Non-platinum group metal (non-PGM) electrocatalysts for the oxygen reduction reaction (ORR) are generally composed of iron, nitrogen, and carbon synthesized through high-temperature pyrolysis. Among the various types of precursors, metal–organic frameworks (MOFs), zeolitic imidazolate framework (ZIF)-8 in particular, have often been used in the synthesis. The pyrolysis of ZIF-8 precursor relies on the use of Zn as a sacrificial metal (SM), and the optimal processing temperatures often exceed 1000 °C to generate active non-PGM catalysts. The high pyrolysis temperature tends to result in heterogeneous active moieties ranging from Fe single atoms to nanoparticles. In this study, we present the synthesis of non-PGM catalysts using Cd as the sacrificial metal instead of Zn. By using Cd, we were able to generate active non-PGM electrocatalysts from the MOF precursors at a low pyrolysis temperature of 750 °C, which helps preserve the single atomic iron active sites.

The utilization of nonprecious metal electrocatalysts for water-splitting may be the ultimate solution for sustainable and clean hydrogen energy. MXene, an emerging two-dimensional material, exhibits many unique properties such as possible metal-like conductivity, hydrophilic surface, and rich chemistry, rendering a group of promising catalysts and catalyst support materials. In this study, exfoliated Ti3C2 MXenes serve as a substrate to perpendicularly grow uniform mesoporous NiCoP nanosheets through an in situ interface-growth strategy and subsequent phosphorization. The obtained Ti3C2@mNiCoP materials with a stable hierarchical sandwich structure possess excellent conductivity, large surface area, and uniform mesopores with high pore volume. With these beneficial properties, the Ti3C2@mNiCoP material exhibits superior overall water-splitting performance compared with that of its building-block counterparts, matching the state-of-the-art water-splitting electrocatalysts.

Due to the scarcity and high cost of precious metals, the hydrogen economy would ultimately rely on non-platinum-group-metal (non-PGM) catalysts. The non-PGM-catalyzed oxygen reduction reaction, which is the bottleneck for the application of hydrogen fuel cells, is challenging because of the limited activity and durability of non-PGM catalysts. A stabilized single-atom catalyst may be a possible solution to this issue. In this work, we employ a coordination-assisted polymerization assembly strategy to synthesize an atomic Fe and N co-doped ordered mesoporous carbon nanosphere (denoted as meso-Fe–N–C). The meso-Fe–N–C possesses a hierarchical structure with a high surface area of 494.7 m2 g–1 as well as a high dispersion of Fe (2.9 wt %) and abundant N (4.4 wt %). With these beneficial structural properties, the meso-Fe–N–C exhibits excellent activity and durability toward the oxygen reduction reaction, outperforming the state-of-the-art Pt/C electrocatalysts.

The new complex hydride Li3(NH2)2I exhibiting fast-ion conduction is reported. Li3(NH2)2I has the characteristic double-layered structure with a = 7.09109(5) Å and c = 11.50958(10) Å (P63 mc). Because of the unique crystal structure, Li3(NH2)2I exhibits fast-ion conductivity of 1 × 10−5 S/cm at 296 K.

No abstract

Controlled synthesis of spinel ZnFe2O4 nanoparticle-decorated ZnO nanofiber heterostructures was carried out with regularly varied particle sizes and uniform distribution. The obtained heterostructures possessed enhanced intrinsic peroxidase-like activity, and the activities regularly changed as the sizes of ZnFe2O4 nanoparticles varied. The heterostructures were further applied in sensitive colorimetric biosensing of urine glucose.

Circadian clocks usually run with a period close to 24 h, but are also plastic and can be entrained by external environmental conditions and internal physiological cues. Two key nutrient metabolites, glucose and vitamin B3 (nicotinamide), can influence the circadian period in both mammals and plants; however, the underlying molecular mechanism is still largely unclear. We reveal that the target of rapamycin (TOR) kinase, a conserved central growth regulator, is essential for glucose- and nicotinamide-mediated control of the circadian period in Arabidopsis. Nicotinamide affects the cytosolic adenosine triphosphate concentration, and blocks the effect of glucose-TOR energy signaling on period length adjustment, meristem activation, and root growth. Together, our results uncover a missing link between cellular metabolites, energy status, and circadian period adjustment, and identify TOR kinase as an essential energy sensor to coordinate circadian clock and plant growth.