Controllable Synthesis Of High-performance Carbon Nanomaterials From Heavy Oil Residue And Its Applications

As the main member of heavy oil residue,petroleum asphalt and fluid catalytic cracking（FCC）slurry have not been widely applied in the downstream petrochemical processes in the refinery due to its complex structure and unworkability.Fortunately,the heavy oil residue is a cheap and readily available carbon source in nature which has great potential applied value as feedstock in producing high value-added carbon nanomaterials such as graphene because it contains a large amount of carbon-rich molecules.The high value-added utilization of heavy oil residue has always been full of challenges and has important practical significance.A neoteric recipe is successfully invented which has synthesized ultralight N,S-doped porous graphene nanosheets（N,S-PGNs）with inexpensive asphalt by the CVD method.The novel approach skillfully avoids the traditional additional process of template removal.To further optimize the structure and composition of the target product,By changing the ratio of asphalt/g-C₃N₄ and the reaction temperature,the structure and composition of the target product were further optimized.Electromagnetic wave absorption tests show that The N-PGNs-2 sample under 750℃demonstrates extraordinary electromagnetic wave absorption performance with best RL_min value of-58.35 d B at 10.8 GHz and 3.45 mm with 15 wt%filler loading,and the bandwidth of RL less than-10 d B reaches 5.84 GHz.Furthermore,with the help of independently developed electrochemical method,the asphalt base N,S-PGNs was coated on the carbon cloth as working electrode which successfully prepared NS-CQDs with good water solubility,dispersion and fluorescence stability by one-step direct current electrolysis synthesis method.The as-prepared NS-CQDs can be effectively used as a fluorescent probe to detect lysine,which plays a crucial role to human body.Ultralight N-rich porous graphene nanosheets（N-PGNs）have been synthesized via a chemical vapour deposition method using FCC slurry as a carbon source and g-C₃N₄ as a substrate.The N-PGNs integrate interesting features including high N doping and large surface area with ultrahigh pore volume,which leads to intriguing performance in electromagnetic wave absorption（EMWA）.When the ratio of FCC slurry and g-C₃N₄reaches 1:2,the maximum reflection loss of the N-PGNs can reach-53 d B with a low filler loading of only 3 wt%,and the effective absorption bandwidth exceeding-10 d B is6.8 GHz with a thickness of 3 mm.It was firstly reported that the absorbing material showed excellent electromagnetic wave absorbing performance with minimum filler loading,which met the development requirements of new absorbing material with strong,wide bandwidth,thin and light weight.In addition,a mild and feasible surface phosphatizing strategy was developed based on the synthesized method of N-PGNs.A highly efficient water electrolysis catalyst doped by nitrogen and phosphorus which was modified by Ni₂P nanoparticle with phosphorus-rich surface shows excellent hydrogen evolution reaction performance.The inferior quality of oil resources is irreversible.As more heavy oil enters China’s refineries and chemical plants,more asphalt and fluid catalytic cracking slurry will be generated.In this paper,the raw material properties of heavy oil residue are skillfully used to prepare high-quality carbon nanomaterials,which demonstrate extraordinary performance in electromagnetic wave absorption performance,carbon quantum dot fluorescence detection and water splitting.We have opened up a new way to realize high value-added utilization of heavy oil residue,and quickened the pace of the carbon peak and carbon neutralization.