Rational Design of Diamond Electrodes

Abstract

Conspectus Diamond electrodes stepped onto the stage in the early 1990s for electroanalytical applications. They possess the features of long-term chemical inertness, wide potential windows, low and stable background currents, high microstructural stability at different potentials and in different media, varied activity toward different electroactive species, reliable electrochemical response of redox systems without conventional pretreatment, high resistance to surface fouling in most cases, and possibility of forming composites with different components such as other carbon materials, carbides, and oxidizes. Most diamond electrodes are prepared in microcrystalline or nanocrystalline form using chemical vapor deposition techniques. Starting from diamond films and diamond composites, numerous nanostructured diamond electrodes have also been produced. The features of diamond electrodes are therefore heavily dependent on the growth conditions and post-treatment procures that are applied on diamond electrodes such as introduced dopant(s), surface termination(s), surface functional group(s), added components, and final structure(s). Numerous applications of diamond electrodes have been explored in the fields of electrochemical sensing, electrosynthesis, electrocatalysis, electrochemical energy storage and conversion, devices, and environmental degradation. This Account summarizes our strategies to design different diamond electrodes, including diamond films, diamond composites, as well as their nanostructures. With respect to diamond films, the modulation of their dopant(s) and surface termination(s) as well as the attachment of functional modifier(s) onto their surface are discussed. Electrochemical hydrogenation and oxygenation of diamond electrodes are detailed at an atomic scale. As the examples of designing diamond electrodes at a molecular scale, photochemical and electrochemical attachment of modifier(s) onto diamond electrodes are shown. Moreover, electrochemical grafting of diazonium salts is proposed as a new technique to identify hydrogenated, hydroxylated, and oxygenated terminations of diamond electrodes. The introduction of additional component(s) into a diamond film to form diamond composites is then overviewed, where a hydrogen-induced selective growth model is proposed to elucidate the preparation of diamond/β-SiC composites. Subsequently, the production of various diamond nanostructures from diamond films and composites by means of top-down, bottom-up, and template-free approaches is shown. Electrochemical application examples of diamond electrodes are overviewed, covering direct electrochemistry of natural Cytochrome c on a hydroxylated diamond surface, sensitive electrochemical DNA biosensing on tip-functionalized diamond nanowires, and construction of high-performance supercapacitors using diamond electrodes and redox electrolytes. Our diamond supercapacitors, also named battery-like diamond supercapacitors or diamond supercabatteries, are highlighted since they combine the features of supercapac...

Diamond Composite: A “1 + 1 > 2” Strategy to Design and Explore Advanced Functional Materials

“…The desired functional molecules or linkers (e.g., nitrophenyl molecules) have been grafted by means of photochemical, electrochemical, and thermal methods. A variety of surface terminations (e.g., H–, OH–, OOH–, and −CO- terminations) on both diamond and SiC phases inside the Dia/SiC composites have been attempted using different dry (e.g., plasma treatment) and wet (e.g., chemical oxidation) methods . With these functional groups, namely, grafted molecules and different surface terminations, the Dia/SiC composites were proven to be biologically active and have been employed for different biomedical applications, such as facilitating selective protein and cell adsorption to guide cell migration.…”

Diamond-like Carbon Patterning by the Submerged Discharge Plasma Technique via Soft Solution Processing

“…The electrochemical tests included cyclic voltammetry (CV) under different scan rates (5−100 mV/s) in a −0.8 to 0 V potential window and electrochemical impedance spectroscopy (EIS) in the frequency range of 0.01 Hz to 100 kHz with an AC perturbation of 5 mV. The areal specific capacitance (C sp ) of the electrodes was precisely determined through CV curves by the formula (1) where I is the current, V is the voltage window, ν is the scan rate, and A is the area of active material.…”

“…Diamond-like carbon (DLC) is well known to outperform amorphous carbon material composed of the sp 3 - and sp 2 -hybridized carbon phase along with hydrogen atoms. , It is well known for low friction, high wear resistance, high thermal stability, chemical inertness, and high electrical resistivity due to the presence of higher sp 3 (diamond phase) in the amorphous carbon matrix. , Its intriguing properties such as high Young’s modulus, wide bandgap, high carrier mobility, low thermal expansion coefficient, and biocompatibility nature of the DLC materials give a unique platform for various technological advancements. Due to its robustness in material properties, it has been applied in a wide range of technological applications such as microelectromechanical systems, protective coatings, field emission, field-effect transistor, and bio-applications. − …”

Regulating the kinetic behaviours of polysulfides by designing an Au–COF interface in lithium–sulfur batteries

“…With the advent of a sustainable and green energy era, the requirements for reliable high-energy-density rechargeable battery systems have increased rapidly. 1,2 However, the limited energy density of battery systems currently under development, such as lithium-ion batteries (z387 W h kg −1 ), contradicts this growing demand. [3][4][5] Owing to the low cost, natural abundance, and high theoretical energy density (z2600 W h kg −1 ), lithium-sulfur (Li-S) batteries are considered one of the most promising highperformance energy storage systems in recent years.…”