Platinum nanoparticle decorated vertically aligned graphene screen-printed electrodes: electrochemical characterisation and exploration towards the hydrogen evolution reaction.

We present the fabrication of platinum (Pt) nanoparticle (ca. 3 nm average diameter) decorated vertically aligned graphene (VG) screen-printed electrodes (Pt/VG-SPE) and explore their physicochemical characteristics and electrocatalytic activity towards the hydrogen evolution reaction (HER) in acidic media (0.5 M HSO). The Pt/VG-SPEs exhibit remarkable HER activity with an overpotential (recorded at -10 mA cm) and Tafel value of 47 mV (vs. RHE) and 27 mV dec. These values demonstrate the Pt/VG-SPEs as significantly more electrocatalytic than a bare/unmodified VG-SPE (789 mV (vs. RHE) and 97 mV dec). The uniform coverage of Pt nanoparticles (ca. 3 nm) upon the VG-SPE support results in a low loading of Pt nanoparticles (ca. 4 μg cm), yet yields comparable HER activity to optimal Pt based catalysts reported in the literature, with the advantages of being comparatively cheap, highly reproducible and tailorable platforms for HER catalysis. In order to test any potential dissolution of Pt from the Pt/VG-SPE surface, which is a key consideration for any HER catalyst, we additively manufactured (AM) a bespoke electrochemical flow cell that allowed for the electrolyte to be collected at regular intervals and analysed via inductively coupled plasma optical emission spectroscopy (ICP-OES). The AM electrochemical cell can be rapidly tailored to a plethora of geometries making it compatible with any size/shape of electrochemical platform. This work presents a novel and highly competitive HER platform and a novel AM technique for exploring the extent of Pt nanoparticle dissolution upon the electrode surface, making it an essential study for those seeking to test the stability/catalyst discharge of their given electrochemical platforms.