Electrochemical CO 2 reduction (CO 2 R) is a sustainable way of producing carbon-neutral fuels, yet the efficiency is limited by its sluggish kinetics and complex reaction pathways. Developing active, selective, and stable CO 2 R electrocatalysts is challenging and entails intelligent material structure design and tailoring. Here we show a graphdiyne/graphene (GDY/ G) heterostructure as a 2D conductive scaffold to anchor monodispersed cobalt phthalocyanine (CoPc) and reduce CO 2 with an appreciable activity, selectivity, and durability. Advanced characterizations, e.g., synchrotron-based X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculation disclose that the strong electronic coupling between GDY and CoPc, together with the high surface area, abundant reactive centers, and electron conductivity provided by graphene, synergistically contribute to this distinguished electrocatalytic performance. Electrochemical measurements revealed a high FE CO of 96% at a partial current density of 12 mA cm −2 in a H-cell and an FE CO of 97% at 100 mA cm −2 in a liquid flow cell, along with a durability over 24 h. The per-site turnover frequency of CoPc reaches 37 s −1 at −1.0 V vs RHE, outperforming most of the reported phthalocyanine-and porphyrin-based electrocatalysts. The usage of the GDY/G heterostructure as a scaffold can be further extended to other organometallic complexes beyond CoPc. Our findings lend credence to the prospect of the GDY/G hybrid contributing to the design of single-molecule dispersed CO 2 R catalysts for sustainable energy conversion.

Bone regeneration disorders are a significant problem in patients with type 2 diabetes mellitus. Bone marrow stromal cells (BMSCs) are recognized as ideal seed cells for tissue engineering because they can stimulate osteogenesis during bone regeneration. Therefore, the aim of this study was to investigate the osteogenic potential of BMSCs derived from type 2 diabetic rats and the pathogenic characteristics of dysfunctional BMSCs that affect osteogenesis. BMSCs were isolated from normal and high-fat diet+streptozotocin-induced type 2 diabetic rats. Cell metabolic activity, alkaline phosphatase (ALP) activity, mineralization and osteogenic gene expression were reduced in the type 2 diabetic rat BMSCs. The expression levels of Wnt signaling genes, such as β-catenin, cyclin D1 and c-myc, were also significantly decreased in the type 2 diabetic rat BMSCs, but the expression of GSK3β remained unchanged. The derived BMSCs were cultured on calcium phosphate cement (CPC) scaffolds and placed subcutaneously into nude mice for eight weeks; they were detected at a low level in newly formed bone. The osteogenic potential of the type 2 diabetic rat BMSCs was not impaired by the culture environment, but it was impaired by inhibition of the Wnt signaling pathway, likely due to an insufficient accumulation of β-catenin rather than because of GSK3β stimulation. Using BMSCs derived from diabetic subjects could offer an alternative method of regenerating bone together with the use of supplementary growth factors to stimulate the Wnt signaling pathway.

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