The use of 3D printing in research and teaching has significantly grown in the past years and has had a major impact on scientific practices. Despite the growing adoption driven by ever decreasing printer prices, the barrier to entry for 3D printing in research laboratories is still high due to the lack of basic reference material targeted at the scientific community. In this Feature, we introduce 3D printing as a tool for use in research laboratories, bridging the gap between scientists and 3D printing technology. This is not another 3D printing review but rather a guide which will help scientists to recognize the usefulness of 3D printing and to make an informed buying decision on their first 3D printer.

Rotating ring disk electrodes (RRDEs) are a powerful and versatile tool for mechanistically investigating electrochemical reactions at electrode surfaces, particularly in the area of electroanalysis and catalysis. Despite their importance, only limited electrode materials (typically glassy carbon, platinum, and gold) and combinations thereof are available commercially. In this work, we present a method employing three-dimensional (3D) printing in conjunction with machined brass components to produce housing, which can accommodate any electrode material in, e.g ., pressed powdered pellet, wafer, rod, foil, or vapor deposited onto a conductive substrate form. In this way, the range and usability of RRDEs is extended. This custom do-it-yourself (DIY) approach to fabricating RRDEs also enables RRDEs to be produced at a significant fraction of the cost of commercial RRDEs. To illustrate the versatility of our approach, coplanar boron-doped diamond (BDD) RRDEs are fabricated for the first time using the approach described. Experimental collection efficiencies for the redox couple FcTMA + /FcTMA 2+ are found to be very close to those predicted theoretically. BDD electrodes serve as an ideal electrocatalyst support due to their low background currents, wide solvent potential window in aqueous solution, and chemical and electrochemical stability in acid and alkali solutions. The BDD RRDE configuration is employed to investigate the importance of surface-incorporated nondiamond carbon in BDD on hydrogen peroxide generation via the oxygen reduction reaction in acid solutions.

For the detection of electrochemically produced hydroxyl radicals (HO • ) from the oxidation of water on a boron-doped diamond (BDD) electrode, electron paramagnetic resonance spectroscopy (EPR) in combination with spin trap labels is a popular technique. Here, we show that quantification of the concentration of HO • from water oxidation via spin trap electrochemical (EC)-EPR is problematic. This is primarily due to the spin trap oxidizing at potentials less positive than water, resulting in the same spin trap-OH • adduct as formed from the solution reaction of OH • with the spin trap. We illustrate this through consideration of 5,5-dimethyl-1-pyrroline Noxide (DMPO) as a spin trap for OH • . DMPO oxidation on a BDD electrode in an acidic aqueous solution occurs at a peak current potential of +1.90 V vs SCE; the current for water oxidation starts to rise rapidly at ca. +2.3 V vs SCE. EC-EPR spectra show signatures due to the spin trap adduct (DMPO-OH • ) at potentials lower than that predicted thermodynamically (for water/HO • ) and in the region for DMPO oxidation. Increasing the potential into the water oxidation region, surprisingly, shows a lower DMPO-OH • concentration than when the potential is in the DMPO oxidation region. This behavior is attributed to further oxidation of DMPO-OH • , production of fouling products on the electrode surface, and bubble formation. Radical scavengers (ethanol) and other spin traps, here N-tert-butyl-αphenylnitrone, α-(4-pyridyl N-oxide)-N-tert-butylnitrone, and 2-methyl-2-nitrosopropane dimer, also show electrochemical oxidation signals less positive than that of water on a BDD electrode. Such behavior also complicates their use for the intended application.

Electrochemical ozone production (EOP) from water is an attractive, green technology for disinfection. Boron doped diamond (BDD) electrodes, grown by chemical vapor deposition (CVD), have been widely adopted for EOP due to their wide anodic window in water and excellent chemical and electrochemical stability. High pressure high temperature (HPHT) synthesis, an alternative growth technique used predominantly for the high-volume synthesis of nitrogen doped diamond microparticles, has been seldom employed for the production of conductive BDD electrodes. In this letter, we demonstrate, for the first time, the use of BDD electrodes fabricated from HPHT conductive BDD microparticles for EOP. The BDD microparticles are first compacted to produce freestanding solid electrodes and then laser micromachined to produce a perforated electrode. The compacted HPHT BDD microparticle electrodes are shown to exhibit high EOP, producing 2.23 ± 0.07 mg L-1 of ozone per ampere of current, at consistent levels for a continuous 20 hr period with no drop off in performance. The HPHT electrodes also achieve a reasonable current efficiency of 23%, at a current density of 770 mA cm-2.