N-doped carbon nanocages： Bifunctional electrocatalysts for the oxygen reduction and evolution reactions

Highly effident metal-free, carbon-based, bi-functional electrocatalysts for the oxygen evolution reaction （OER） and oxygen reduction reaction （ORR） have attracted increased attention for use in electrochemical energy conversion systems, owing to their low cost and high activity. In this work, N-doped carbon nanocages （N-CCs） with a porous self-supported architecture and high specific surface area are synthesized by a facile interfacial assembly synthetic route. The materials are comprehensively characterized by scanning electron microscop36 transmission electron microscopy, nitrogen adsorption-desorption experiments, X-ray diffraction, and X-ray photoelectron spectroscopy. Cyclic voltammetry , chronoamperometry, and linear sweep voltammetry demonstrate that the as-prepared N-CC could serve as an effective metal-free electrocatalyst with excellent catalytic activity, long-term operation durability, and excellent methanol tolerance for the ORR in alkaline media. In the presence of 3 mM methanol, the half wave potential of the N-CCs for the ORR is 190 mV; this is more positive than that of the commercial Pt/C electrocatalyst. Meanwhile, the N-CCs also show an OER activity comparable to that of the commercial Ru/C electrocatalyst, revealing their bifunctional property.

Highly Efficient Dye-sensitized Solar Cells by Co-sensitization of Organic Dyes and Co-adsorbent Chenodeoxycholic Acid

Approach to highly efficient dye-sensitized solar cells(DSSCs)by co-sensitization of organic dyes,AZ6+AZ5 with co-adsorbent chenodeoxycholic acid(CDCA)is presented.The power conversion efficiencies(PCEs)of 8.55%and 8.31%are obtained from DSSCs co-sensitized by AZ6(0.3 mmol/L)+AZ5(0.1 mmol/L)with CDCA concentration of 5 and 20 mmol/L in one step cocktail,respectively.The latter shows high stability in a period of 653 h under ambient conditions.