Low‐Temperature Conversion of Alcohols into Bulky Nanoporous Graphene and Pure Hydrogen with Robust Selectivity on CaO

Abstract

The direct conversion of biorenewable alcohols into value‐added graphene and pure hydrogen (H2) at benign conditions is an important challenge, especially, considering the open carbon‐reduced cycle. In this study, it is demonstrated that inexpensive calcium oxide (CaO, from eggshells) can transform alcohols into bulky nanoporous graphene and pure hydrogen (≈99%) with robust selectivity at the temperature as low as 500 °C. Consequently, the growth of graphene can follow the direction of alcohol flow and uniformly penetrate into bulky nanoporous CaO platelets longer than 1 m without clogging. The experimental results and density functional theory calculations demonstrate that alcohol molecules can be catalytically carbonized on the surface of CaO at low temperature. The concept of the comprehensive utilization of biomass‐derived alcohols offers a carbon‐negative cycle for mitigating global warming and the energy demand.

Plasma-enabled catalyst-free conversion of ethanol to hydrogen gas and carbon dots near room temperature

“…Ethanol produced from the conversion of abundant biomass resources such as low-cost non-edible lignocelluloses, is currently contributing for more than 100 billion litres of fuel to the global energy market in an effort to build a more sustainable future [1][2][3]. Due to its notable advantages including renewability, low toxicity, affordability, ease of storage and high hydrogen content, ethanol has also emerged as a promising feedstock to produce highervalue and cleaner energy carrier, i.e.…”

Precise synthesis of N-doped graphitic carbon via chemical vapor deposition to unravel the dopant functions on potassium storage toward practical K-ion batteries

“…During CVD reaction, both eggshell and CaCO3 are decomposed into CaO (Fig. S5 in the ESM), which supports the growth of graphene [30]. Intriguingly, HENC tends to grow vertically on CaO and expose ample edge-defective sites for nitrogen doping (Fig.…”

Porous monoliths of 3D graphene for electric double‐layer supercapacitors

“…Various oxides have the ability to act as substrates for growing few-layer graphitic or graphene under CVD conditions, such as MgO, 81 ZnO, 82 CaO, [83][84][85] SiO 2 , [86][87][88][89][90] and so forth. The oxides can prompt the decomposition of the carbon source and the deposition of graphitic carbon on their surface.…”

“…CaO is a low‐cost oxide, which is extracted from Ca(OH) 2 , 83 seashells, 84 eggshells, 85 and so forth. Tang et al 83 reported a CaO‐templated growth of hierarchical porous graphene.…”

“…Utilizing the lime slaking of CaO, graphene foams were molded into arbitrary shapes macroscopically. Han et al 85 reported that CaO derived from eggshells transformed alcohols into nanoporous graphene at the temperature as low as 500°C.…”