High efficient and non-precious metal electrocatalysts for oxygen evolution reactions (OER) and oxygen reduction reactions (ORR) are at the heart of key renewable-energy technologies. Nevertheless, developing highly-active bi-functional catalysts at low cost for both OER and ORR still remains a huge challenge. In this paper, Co3O4 nanocrystals embedded in N-doped mesoporous graphitic carbon layer/multiwalled carbon nanotubes (MWCNTs) hybrids are prepared by a facile carbonization and subsequent oxidation process of MWCNTs-based metal-organic framework (MOF). As a result, in alkaline media, the hybrid material catalyzes OER with an onset potential of 1.50 V (vs reversible hydrogen electrode) and over-potential only of 320 mV to achieve a stable current density of 10 mA cm -2 for at least 25 h. The same hybrids also exhibit similar catalytic activity but superior stability to commercial 20 wt% Pt/C catalyst for ORR, making it a high-performance cheap bi-catalyst for both OER and ORR. The design concept of nonmetal-doped and precious-metal-free electrocatalysts from MOF can be extended to fabricate other novel, stable and easy to use catalyst system for advanced applications.

Single Fe atom dispersed carbon nanostructures show promising oxygen reduction reaction (ORR) activities for renewable energy applications. Nevertheless, the microenvironment of the single Fe atoms needs to be further engineered to optimize the catalytic performance, which is challenging. In this work, we develop a NaCltemplate pyrolysis method to fabricate single Fe atom catalysts with atomically dispersed Fe−heteroatom (N, S) bridge sites anchored on carbon nanosheets. The N and S coordinated Fe atomic sites (FeN 3 S) are found to induce charge redistribution, lowering the binding strength of oxygenated reaction intermediates and leading to fast reaction kinetics and good oxygen reduction activity. Our work provides an effective method to regulate the microenvironment of single-atom catalysts for optimizing electrocatalytic performance.

Background: Aberrant expression of circular RNAs contributes to the initiation and progression of cancers, but the underlying mechanism remains elusive. Methods: RNA-seq and qRT-PCR were performed to screen differential expressed circRNAs between gastric cancer tissues and adjacent normal tissues. Candidate circRNA (circMRPS35) was screened out and validated by qRT-PCR. Cell proliferation and invasion ability were determined by CCK-8 and cell invasion assays. RNA-seq, GO-pathway, RNA pull-down and ChIRP were further applied to search for detailed mechanism. Results: Here, a novel circRNA named circMRPS35, was screened out by RNA-seq in gastric cancer tissues, whose expression is related to clinicopathological characteristics and prognosis in gastric cancer patients. Biologically, circMRPS35 suppresses the proliferation and invasion of gastric cancer cells in vitro and in vivo. Mechanistically, circMRPS35 acts as a modular scaffold to recruit histone acetyltransferase KAT7 to the promoters of FOXO1 and FOXO3a genes, which elicits acetylation of H4K5 in their promoters. Particularly, circMRPS35 specifically binds to FOXO1/3a promoter regions directly. Thus, it dramatically activates the transcription of FOXO1/3a and triggers subsequent response of their downstream target genes expression, including p21, p27, Twist1 and E-cadherin, resulting in the inhibition of cell proliferation and invasion. Moreover, circMRPS35 expression positively correlates with that of FOXO1/3a in gastric cancer tissues. Conclusions: Our findings not only reveal the pivotal roles of circMRPS35 in governing histone modification in anticancer treatment, but also advocate for triggering circMRPS35/KAT7/FOXO1/3a pathway to combat gastric cancer.