Fig. 1. Potential-induced structural changes of Pt(111) electrodes in the potential region between H-UPD (0.05 VRHE) and surface oxide formation (0.95 VRHE) revealed using in situ surface X-ray scattering. Reprinted with permission from Ref. [37]. Copyright 2016, American Chemical Society.

Fig. 2. (a-c) In situ constant current STM images of the as-prepared Pt(332) electrode at 0.1 VRHE in a N2-saturated sulfuric acid solution. Reprinted with permission from Ref. [34]. Copyright 2018, American Chemical Society. (d) Cyclic voltammograms (CVs) measured on Pt(553) showing the first (red line) and second cycles (black line) after holding the electrode at -0.2 VRHE for 60 s. Reprinted with permission from Ref. [36]. Copyright 2019, American Chemical Society. The author(s) and J. Phys. Chem. Lett., published by the American Chemical Society under the terms of the Creative Commons CC BY license (https://creativecommons.org/licenses/by-nc-nd/4.0/). (e) Contour of the corrugation along the dotted line marked at the upper end of panel (b). Reprinted with permission from Ref. [34]. Copyright 2018, American Chemical Society. (f) Steady-state CVs of the Pt(332) electrode in the N2-saturated sulfuric acid solution; inset shows a spherical model of a perfect Pt(332) surface in top and side views. Reprinted with permission from Ref. [34]. Copyright 2018, American Chemical Society.

Fig. 3. (a) Some representative i-E curves for HER (NS and PS indicate negative and positive scans, respectively) on Pt(111) in a N2-saturated sulfuric acid solution from -0.1 to 0.65 VRHE: right after flame annealing (black line), first (red line), second (blue line). (b) The corresponding CVs of the Pt(111)-electrolyte interface recorded after HER scans, as described in Fig. 2(a). (c) Schematic of HER-induced H uptake at defect sites on Pt(111), which increased the HER activity. Reprinted with permission from Ref. [10]. Copyright 2021, AIP publishing.

Fig. 4. In situ constant current STM images of the as-prepared Pt(332) surface at 0.1 VRHE in a CO-saturated sulfuric acid solution (a), and the corresponding close-up STM images (b). High-resolution EC-STM image (c) and ball model illustrating the spatial structure (d) of CO adsorbed on Pt(332). Reprinted with permission from Ref. [34]. Copyright 2018, American Chemical Society.

Fig. 5. STM images of Pt(111) (a,b) and Pt(20, 19, 19) (d,e) at 0.55 VRHE in a CO-saturated perchloric acid solution before potential cycling (a,d) and after 30 potential cycles (b,e). (c) Corresponding CVs of Pt(111) in the CO-saturated perchloric acid solution. (f) Corresponding CVs of Pt(111) in a N2-saturated perchloric acid solution. Reprinted with permission from Ref. [16]. Copyright 2013, American Chemical Society.

Fig. 6. STM images of the as-prepared bare Ru(0001) surface (a) and as-prepared 0.32 ML of Pt-modified Ru(0001) surface (b). STM images of the same electrode collected after potential cycling up to 0.9 VRHE (c) and 1.05 VRHE (d) in a CO-saturated solution. (e) A close inspection of the potential-induced surface restructuring of the 0.28 ML of as-prepared Pt deposited on Ru(0001) after cycling potential up to 0.9 VRHE and 1.05 VRHE in a CO-saturated solution, affording new, highly active sites and enhanced CO oxidation activity. (f) CV of the Ru(0001) electrode in a sulfuric acid solution with an increased upper-potential limit. (g) CV of Ru(0001) (black line), 0.32 ML of Pt/Ru(0001) (blue line), and 0.40 ML of Pt/Ru(0001) (red line) in the sulfuric acid solution. Reprinted with permission from Ref. [60]. Copyright 2014, WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Fig. 7. (a) Sequences of video-STM images (6 × 6 nm2) at 0.55 VRHE showing step fluctuations and defect formation/annihilation at steps on Pt(111). (b) Image sequences of Pt(111) at 0.55 VRHE showing the slow diffusion of defects (motion is indicated by arrows) in the highly dynamic, apparent (1 × 1) CO adlayer. Electrolyte: CO-saturated 0.1 mol/L H2SO4. Reprinted with permission from Ref. [35]. Copyright 2020, Royal Society of Chemistry.