SEM images of RW-based samples. (a) Pristine wood, inside: carbonized wood; (b) Surface of RW-1000 (c) Surface and enlargement view of NRW-1000; (d) Surface peeled porous ultrathin GLCNs and enlarged view of NRW-1000; (e) The porous ultrathin GLCNs attract on the surface of NRW-1000; (f-i) Element mapping of NRW-1000.