## 3 Results and Discussion  
The entire synthetic route of Co-GPC is illustrated in Scheme 1. Firstly, the GO was functionalized sequentially by amine groups and 2-(dodecylthiocarbonothioylthio)-2-methylpropionic acid (DDAT) to obtain a macromolecular initiator of GO-DDAT. As shown in Figure 1a, the broad band at 3430 cm\({}^{-1}\) was attributed to the O-H stretching vibrations of the GO sheets, originating from carboxylic acid and hydroxyl groups, as well as the adsorbed water [34]. The two peaks at 1720 and 1645 cm\({}^{-1}\) corresponded to C=O and C=C stretching vibrations of the GO, respectively [35]. For the GO-DDAT (Figure 1b), the peak of the O-H stretching vibrations was suppressed, whilst the hydrogen bond interactions at 1108 cm\({}^{-1}\) were observed clearly, suggesting the existence of an amido linkage esterified from the carboxylic group. Furthermore, the absorption bands at 2930 and 2861 cm\({}^{-1}\) were ascribed to the methylene and methyl stretching of DDAT, indicating the successful grafting of the chain-transfer agent of DDAT onto the surface of the GO [33]. The grafting ratio of DDAT in GO-DDAT calculated using elemental analysis reached 3.3%. Used as the RAFT macromolecular chain-transfer agent of GO-DDAT, monomers of 1,4-divinylbenzene and 4-vinylbenzyl could be grafted onto the GO surface through traditional RAFT emulsion polymerization in water, with the initiator of AlBN and emulsifier of PVA. Owing to the existence of methyl chloride, 5,10,15,20-tetra(4-pyridyl) Co (II) porphyrin (Co (TPyP)) could be crosslinked onto the GO-PVD through the nucleophilic substitution reaction to form Co-GO-PVD. The 2D porous hypercrosslinked polymer of Co-GHCP was then prepared using a FeCl\({}_{3}\)-catalyzed Friedel-Crafts reaction. Compared to that of GO-DDAT, Co-GHCP exhibited a significant peak at 1610 cm\({}^{-1}\) (skeletal vibrations from the graphitic domains), attributed to the aromatic C=C. The vibration peaks at -1400 and -1000 cm\({}^{-1}\) could be attributed to the -Co-N- bonds of the porphyrin rings [36]. Additionally, a distinctive peak at 820 cm\({}^{-1}\) corresponding to C-Cl stretching was detected, which suggested a low reaction activity for the Friedel-Crafts reaction in the hypercrosslinked polymer, due to the restriction motion of the polymeric chains (Figure 1c) [37]. After the heat treatment, the disappearance of the peak at 820 cm\({}^{-1}\) in the Co-GPC indicated the complete transformation of the unreacted Ar-CH\({}_{2}\)-Cl groups for the graphene-like carbon structure. More importantly, the typical peaks of the porphyrin group still existed (Figure 1d). All these results confirmed the successful doping of cobalt ion onto the skeleton of the graphene-coupledhypercrosslinked polymer and corresponding porous carbon. In the control experiments, GHCP and GPC were also achieved by using TPyP instead of Co (TPyP), according to the same procedure. The thermal behaviors of Co-doped Co-GHCP and un-doped GHCP were recorded using thermal gravimetric analysis (TGA) at a heating rate of 20 \({}^{\circ}\)C min\({}^{-1}\) under a nitrogen atmosphere. Thermogravimetric (TGA) curves of the Co-GHCP and GHCP were recorded in Figure S1, where the weight loss (\(<\)10%) below 250 \({}^{\circ}\)C was attributed to the evaporation of adsorbed small molecules and crystal water. For the GHCP, only 8% weight loss was achieved at a temperature of 350 \({}^{\circ}\)C. Rapid weight loss occurred in the range between 400 to 500 \({}^{\circ}\)C, indicating the decomposition of the alkane structure in the main chain of the hypercrosslinked polymer and some oxygen-containing groups in  
Figure 1: FTIR spectra of (a) GO, (b) GO-DDAT, (c) Co-GHCP, and (d) Co-GPC. the GO. These results demonstrated that the graphene-coupled hypercrosslinked polymer exhibited high thermal stability. After 500 \({}^{\circ}\)C, the residual weight of the GHCP was almost constant, which suggested that the samples had been converted to stable carbon. The residual weight of the GHCP at 800 \({}^{\circ}\)C was 28.2 wt%.