Dual‐Functional NaCl Template Strategy towards Synthesis of Metal‐Free Sulfur/nitrogen co‐Doped Carbon Nanosheets Catalysts for Oxygen Reduction Reaction

Abstract

Developing eco-friendly, high-efficiency and cost-effective catalysts for oxygen reduction reaction are significantly crucial for the application of direct-methanol fuel cells. The metal-free sulfur/nitrogen in-situ co-doped carbon nanosheets are prepared through polymerization process and carbonization process using aniline as a nitrogen source, 4-aminobenzenesulfonamide as a sulfur source and NaCl as a template and protective layer. The obtained catalysts show the obvious two dimensional nanosheet structure with successful doping of S and N. Benefiting from high contents of S atoms and N atom, high special surface area and graphitic degree, well-ordered micropores and synergetic interaction between thiophenic-S, pyridinic N and graphitic N, the optimal catalyst S3/N-CNS800 shows excellent oxygen reduction performance with 13.2 mV more positive half-wave potential than that of 20% Pt/C, superior long-term durability and tolerance to methanol crossover. Results and DiscussionThe synthesis of the carbon nanosheets is described in the Experimental Section, as shown in Scheme 1, which contains [a] C.

Solar-Light-Responsive Zinc–Air Battery with Self-Regulated Charge–Discharge Performance based on Photothermal Effect

“…The high-resolution N 1s XPS spectra are deconvoluted into four peaks at 398.56, 399.77, 401.35, and 405.19 eV (Figure h), which can be ascribed to pyridinic N, pyrrolic N, graphitic N, and oxidized N. , Obviously, the ratio of pyrrolic N for FeNi-S,N-HCS is higher than that of FeNi-N-HCS and N-HCS, which contributes to the superior catalytic performance of FeNi-S,N-HCS. The peaks at 162.04, 163.9, 165.01, and 168.7 eV in the high-resolution S 2p XPS spectra correspond to S 2p 3/2 , S 2p 1/2 , C–S–C, and SO 4 2– , demonstrating that S exists in FeNi-S,N-HCS composite in the form of C–S bonds and metal–S bonds (Figure i). − …”

Tuning the electrochemical capacitance of carbon nanosheets by optimizing its thickness through controlling the carbon precursor in salt‐template

“…Moreover, salt-templated method offers tunability of structural modification in the derived carbon materials by simply varying the precursor and template ratio, leading to the formation of either porous carbon or carbon nanosheets. 18,19 In addition, the use of water-soluble salt templates makes it possible to attach functional groups and redox additives in the derived carbon nanomaterials. 20 It is also possible to enhance the SSA and pore structure of template-derived carbon by post-activation.…”

“…Interestingly, these template methods are greener, recyclable and can minimize the toxic chemicals usage for the synthesis of porous nanocarbon materials. Moreover, salt‐templated method offers tunability of structural modification in the derived carbon materials by simply varying the precursor and template ratio, leading to the formation of either porous carbon or carbon nanosheets 18,19 . In addition, the use of water‐soluble salt templates makes it possible to attach functional groups and redox additives in the derived carbon nanomaterials 20 .…”

Iron‐Containing Nitrogen‐Doped Carbon Nanomaterials Prepared via NaCl Template as Efficient Electrocatalysts for the Oxygen Reduction Reaction

“…Water-soluble salts, such as sodium chloride can be very easily removed after synthesis and the salt can act as a protective layer during pyrolysis, reducing the evaporation of the doping atoms. [31] NaCl crystals have been used as a structure-directing agent in the pyrolysis of a large variety of organic precursors, such as glucose, [14,32,33] sucrose, [15] chitosan, [34] citric acid, [35] Llysine, [36] cysteine, [37] beancurd, [38] polyacrylamide, [16] polyaniline, [17] vitamin B12 [39] and ZIF-8. [40] The resulting catalyst materials have shown high electrocatalytic activity for ORR.…”