Physically and chemically modified zeolite templated nitrogenous carbons for enhanced hydrogen adsorption

Abstract

Carbon materials have great potential for hydrogen adsorption due to their remarkable specific surface area, unique pore size characteristics and ability to functionalize with metal or non-metal. In this work, zeolite templated carbons were physically and chemically modified by varying preparation conditions to study their impact on structure and hydrogen adsorption capacity. The resultant templated carbons showed surface area in the range of 608–1665 m²/g and pore volume between 0.63 to 1.00 cc/g, with 28–48 % microporosity depending on synthesis conditions. The surface area and pore volume increased with increasing carbon deposition temperature from 650 to 750 °C and both decreased at higher carbon deposition temperature of 850 °C. At heat treatment temperature of 900 °C, the surface area and pore volume of templated carbons were observed to be higher. Incorporation of nitrogen heteroatom in carbon matrix during carbon deposition might have facilitated porosity. Use of argon as carrier gas resulted in the highest surface area (1665 m²/g), micropore area (597 m²/g) and pore volume (1.0 cc/g). The same templated carbon showed maximum hydrogen adsorption capacity of 0.20 and 2.81 wt% at 25 and –196 °C, respectively at 15 bar. On addition of platinum to templated carbon, the hydrogen adsorption capacity was significantly improved from 0.20 to 0.28 wt% at 25 °C and from 2.81 to 3.24 wt% at –196 °C. The strong affinity of Pt for hydrogen might have enhanced hydrogen adsorption.