2D Hexagonal Boron Nitride (2D‐hBN) Explored as a Potential Electrocatalyst for the Oxygen Reduction Reaction

Abstract

[a] 1IntroductionAs the availability of naturale nergy resources depletes,i t has become increasingly important to finda lternative means of energyp roduction [1].T he most common alternativest of ossil fuels are renewable sources such as hydroelectric power and wind turbines,a nd for transportation purposes,e lectrolysers for fuel cells.T he latteri sa n electrochemical device that relies on the oxidation of af uel, such as methanol, at aw orking electrode (anode), while the protons liberated act as ar educinga gent to oxygen in the cathodicp art of the fuel cell. Research into proton exchange membrane (PEM) fuel cells,i nw hich the oxygen reduction reaction( ORR) occurs,i sd irected towardsi mproving power output, efficiency,a nd longevity,s uch that devices become viable for the transportation fuel cell market [ 2].TheO RR occurs at the cathode of PEM fuel cells and has proved to be problematic (dependent upon the catalyst utilised), primarily limiting the lifetimes of devices due to electrode fouling [3,4].F or example,P EM fuel cell degradation [2] is synonymous with the ORR due to the formationo fh ydrogen peroxide (H 2 O 2 )w hen using catalysts that reduce oxygen via at wo electron pathway [5].F urthermore, slow electront ransfer kinetics during the ORR can potentially result in a5 0% voltage loss and reduce the performance of aP EM fuel cell [2,6].T here Abstract:C rystalline2 Dh exagonal Boron Nitride( 2D-hBN) is explored as ap otential electrocatalyst towards the oxygen reduction reaction (ORR) when electrically wired via ad rop-casting approach upon ar ange of carbon based electrode surfaces;n amely,g lassy carbon (GC), boron-dopedd iamond (BDD), and screen-printed graphitic electrodes (SPEs). We consider the ORR in acidic conditions and critically evaluate the performanceo fu nmodified and 2D-hBN modified electrodes,i mplementing coverage studies (commonly neglected in the literature) in order to ascertain the true impact of this novel nanomaterial. Theb ehaviouro f2 D-hBN towards the ORR is shown to be highly dependent upon both the underlying carbon substrate and the coverage/mass utilised.2 D-hBN modified SPEs are foundt oexhibit the most beneficial response towards the ORR, reducingt he peak potential by ca. 0.28 Vw hen compared to an unmodified/bare SPE. Such improvements at this supporting substrate are inferred due to favourable 2D-hBNi nteraction with ridged surfaces exposing ah igh proportion of edge regions/sites, where conversely,w es how that relatively smooth substrate surfaces (such as GC) are less conducivet owards successful 2D-hBN immobilisation.I nt his paper, we reveal for the first time (in the specific caseo fu sing ar ough supporting substrate) that 2D-hBN gives riset o beneficial electrochemical behaviourt owards the ORR. Unfortunately,t his material is not considered an electrocatalyst for use within fuel cells given that the estimated number of electrons transferred during the ORRr anges between 1.90-2.45 for different coverages,i ndicatingt hat the ORR at 2D-hBN predomi...

Surfactant-exfoliated 2D hexagonal boron nitride (2D-hBN): role of surfactant upon the electrochemical reduction of oxygen and capacitance applications

“…17 The observed benecial response at pristine 2D-hBN modied SPEs was attributed to the interaction between 2D-hBN and the roughness of the underlying SPE, whereas the comparatively smooth surface of a GC electrode hindered this. 17 Another key are within the energy sector is improving the overall power of energy storage devices. A fundamental high power solution is to utilise advanced electrode materials within supercapacitor devices.…”

“…6 We have previously reported that surfactant-free (pristine) 2D-hBN nanosheets exhibit an electrocatalytic behaviour towards the ORR when immobilised upon SPEs. 17 Pristine 2D-hBN reduced the potential required for the ORR to occur by ca. 0.28 V in comparison to unmodied/ underlying SPEs.…”

“…17 Interestingly, no such benecial response was observed for pristine 2D-hBN when it was modied/ supported on GC and boron doped diamond (BDD) underlying electrodes. 17 The observed benecial response at pristine 2D-hBN modied SPEs was attributed to the interaction between 2D-hBN and the roughness of the underlying SPE, whereas the comparatively smooth surface of a GC electrode hindered this. 17 Another key are within the energy sector is improving the overall power of energy storage devices.…”

Hexagonal Boron Nitride Functionalized with Au Nanoparticles—Properties and Potential Biological Applications

“…The most important was to assess the shape and thickness of h-BN flakes before and after the exfoliation process. The commercial h-BN flakes were very thick (~300 nm) [ 27 , 28 ], which corresponded to 900 layers in the individual flake. A large number of flakes was aggregated and connected to each other.…”

Surfactant exfoliated 2D hexagonal Boron Nitride (2D-hBN) explored as a potential electrochemical sensor for dopamine: surfactants significantly influence sensor capabilities

“…† Analysis of the EDX map shows uniform distribution of B and N atoms with a ratio (1 : 1) of 20.12 at% and 18.81 at% B : N respectively and this composition correlates with expected values for surfactant exfoliated 2D-hBN. 28…”