Facile and controllable synthesis of hydroxyapatite/graphene hybrid materials with enhanced sensing performance towards ammonia

Abstract

In this work, needle-like and micro-spherical agglomerates of nanocrystalline hydroxyapatite (HA) were successfully assembled on the surface of graphene sheets with the aid of dopamine having two roles, as a template and a reductant for graphite oxide during the process of self-polymerization. The crystalline structure and micromorphology of HA can be conveniently regulated by controlling the mineralization route either with a precipitation (cHA/GR) or biomimetic methodology (bHA/GR). Both the composites exhibit improvements of ∼150% and ∼250% in sensitivity towards the sensing of ammonia at room temperature, compared with that of bare graphene. The combination of the multi-adsorption capability of HA and the electric conductivity of graphene is proposed to be the major reason for the observed enhancements. Gas sensing tests demonstrated that the HA/GR composites exhibit excellent selectivity, high sensitivity and repeatable stability towards the analytical sensing of ammonia.

Investigating the mechanical behavior of hydroxyapatite-reduced graphene oxide nanocomposite under different loading rates

“…On the other hand, the angle between (211) and (300) planes in HA was about 27 degrees. Therefore, the rGO surface was tangible to the HA (300) planes [46,47]. By comparing FFT analyzes ( figure 7(h)), it is found that rGO cross section analysis was galactic.…”

Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications

“…This composite presented an excellent in vitro biomineralization after soaking in SBF. In other studied too, HAp was deposited on graphene sheets [534], GO sheets [535], or functionalized graphene nanosheets [536,537,538]. Usually, the nanocomposites are synthesized as nanoparticles in solutions and should be separated by centrifugation.…”

High Yield Synthesis of Hydroxyapatite (HAP) and Palladium Doped HAP via a Wet Chemical Synthetic Route

“…In addition to these applications, the specific characteristics of HAP, such as low water solubility and high stability under oxidising and reducing conditions, make this material suitable as a sorbent in the purification of wastewater and removal of a variety of heavy metals, such as arsenic (III), selenium (IV), lead (II), cadmium (II), cobalt (II) or nickel (II) from contaminated industrial aqueous waste [5][6][7][8][9]. Another powerful application of HAP is the determination of ammonia for applications such as environmental pollution control, reported by Zhang et al [10], who describe electrochemical detection of ammonia (at room temperature) using a composite of HAP/graphene which exhibits a significant improvement in the analytical sensitivity compared to that of a bare graphene sensor. Furthermore, Kanchana et al [11] employed HAP towards the electrochemical detection of uric acid demonstrating a limit of detection of 142 nM, which was applied to human urine and blood serum.…”