Ultrafast microwave-assisted synthesis of highly nitrogen-doped ordered mesoporous carbon

Highly doped porous carbons are highly promising for a variety of applications, but it is challenging to obtain high heteroatom content with well-defined pore morphology without using an inorganic template. Here, we describe a simple microwave accelerated approach to generate high surface area, ordered mesoporous carbons with controllable nitrogen content directly on a nickel foam framework. Cooperative assembly of phenolic resin (resol) and Pluronic F127 coated on the nickel foam provides a route to hierarchically structured composites to promote efficient transport, while melamine provides the nitrogen source. The strong interaction of microwaves with nickel rapidly and locally heats the precursors to yield nitrogen doped mesoporous carbon with high surface areas attached to the nickel foam within 3 min. As the microwave power is increased, the total nitrogen incorporated into the framework increases with a preference for pyridinic nitrogen. With this microwave assisted synthesis, the nitrogen content within the mesoporous carbons can approach 20 at%, while a relatively large average pore size (~7.5 nm) is obtained from the Pluronic template without any swelling agents or inorganic scaffold. To illustrate their potential, these nitrogen-doped mesoporous carbons are demonstrated as electrocatalysts for the oxygen reduction reaction (ORR) with stable performance over 5000 cycles. This solid state microwave fabrication methodology produces highly nitrogen doped ordered mesoporous carbons with characteristics difficult to obtain with traditional soft templating and this methodology should be extendable to a wide range templates and heteroatom dopants.