Urea-crosslinked 3D graphene oxide/MXene-SO₃/cyclodextrin films for efficient and sustainable biodiesel production

Biodiesel, a renewable bio-based transport fuel consisting of alkyl esters of long-chain fatty acids, is gaining attention as an alternative to non-renewable petroleum diesel. We prepared adjustable interlayer spacing urea-crosslinked 3D graphene oxide/MXene-SO₃/cyclodextrin (MGUC) film to achieve efficient and sustainable biodiesel production. Ti₃C₂T_X (MXene) grafted sulfonic acid groups as acid-catalytic sites of the film with graphene oxide (GO) via urea cross-linking and doping cyclodextrin (CD) to construct multistage pore structures (internal pore structures generated by urea cross-linking as well as CD host-guest structures) synergistically catalyzed biodiesel production. Meanwhile, the heterogeneous carbon-based materials based on GO and MXene-S have excellent photothermal efficiency, which can achieve 95.6 % biodiesel conversion at 4 h and maintain 75.32 % activity after 8 cycles. We verified the reason for the high catalytic activity of the MGUC films, which rationalized the fast mass transfer mechanism of CD by Density functional theory (DFT)and verified the transport mechanism of the heterojunction for efficient photothermal. Therefore, this CD carbon-based solid acid film catalytic platform provides a new direction for the green and efficient preparation of bioenergy.