We chose g-C3N4 as the host materia

We chose g-C3N4 as the host material for the synthesis of
the electrocatalyst mainly for the following reasons: (1) g-C3N4
is composed of inexpensive, earth-abundant elements, (2) gC3N4 can easily be prepared from commercially available and
inexpensive starting materials, (3) g-C3N4 is chemically quite
stable due to the strong covalent bonds involved in it [30–32],
and (4) g-C3N4 contains nanosize cavities composed of three
heptazine units (Fig. 1E), which can function as macrocyclic ligands for inclusion of various catalytically active metallic ions
or nanoparticles [33–35]. However, these appealing structural
features of g-C3N4 need to be structurally/compositionally “upgraded” with electrocatalytically active groups to fully take
advantage of them and utilize the material for electrocatalysis of
HER.
To this end, we have carried out the synthesis of Cu-C3N4 catalysts. The synthetic method we employed to make the catalysts
involved a one-step self-assembly procedure (see Section 2 for
details of the experimental procedures). This method was adopted
from previously reported synthesis of Fe3+(Zn2+)-doped g-C3N4
hybrid materials by Wang et al. [33]. It is worth emphasizing here
though that despite the similarities in structures between the CuC3N4 reported here and the Fe3+(Zn2+)-C3N4 reported in Ref. [33], as
well as the similarities of the synthetic methods employed in both
cases, it was only the Cu-doped g-C3N4 that we made showed electrocatalytic activity toward H2 evolution reaction. In other words,
our attempted tests of electrocatalysis of HER using the Fe3+(Zn2+)-
C3N4 materials that we made as reported by Wang et al. [33] as
well as many other types of metal ion containing C3N4 were all
unsuccessful.
In a typical synthesis, copper(II) salt (e.g., CuCl2) was used as
the source of copper, and dicyandiamide was used as an organic
monomer for making the g-C3N4. When the mixture of copper(II)
salt and dicyandiamide was thermally treated at elevated temperature (500 ◦C) under N2 protection, the dicyandiamide became
g-C3N4 while, at the same time, the copper ions were directly
self-assembled in situ within the dicyandiamide-derived g-C3N4,
forming the desired Cu-C3N4 materials. The relative amount of
copper in the Cu-C3N4 material, which can be determined by thermogravimetric (TG) analysis (see below), was varied (or controlled)
by changing the molar ratio of copper(II) salt and dicyandiamide. In
this work, two Cu-C3N4 samples with different amount of copper,
denoted hereafter as 0.12Cu-C3N4 and 0.31Cu-C3N4, because the
molar ratios of Cu/g-C3N4 in them were found to be 0.12:1.00 and
0.31:1.00, respectively, (see below) were synthesized. Pure g-C3N4
was also synthesized to serve as a reference material to compare
the structures, properties, and electrocatalytic activities with those
of Cu-C3N4 materials. The BET surface areas of g-C3N4 and Cu-C3N4
materials are found to be nearly similar (e.g., 10 cm2/g and 6 cm2/g
for g-C3N4 and 0.12Cu-C3N4, respectively).

Kết quả (Việt) 1:

Chúng tôi đã chọn g-C3N4 như là vật liệu máy chủ lưu trữ cho việc tổng hợpelectrocatalyst chủ yếu là vì lý do sau: g-C3N4 (1)bao gồm các yếu tố không tốn kém, trái đất phong phú, gC3N4 (2) có thể dễ dàng được chuẩn bị từ thương mại có sẵn vàtài liệu bắt đầu không tốn kém, g-C3N4 (3) là hóa học kháổn định do các liên kết liên mạnh mẽ tham gia vào nó [30-32],và g-C3N4 (4) có nanosize sâu răng bao gồm bađơn vị heptazine (hình 1E), có chức năng như macrocyclic ligand phát của các ion catalytically hoạt động bằng kim loạihoặc hạt nano [33-35]. Tuy nhiên, những hấp dẫn cấu trúctính năng của g-C3N4 cần phải được cấu trúc/compositionally "nâng cấp" với electrocatalytically hoạt động nhóm để hoàn toàn cólợi thế của họ và sử dụng các tài liệu cho electrocatalysis củaCỦA CÔ.Để kết thúc này, chúng tôi đã thực hiện tổng hợp các chất xúc tác Cu-C3N4. Các phương pháp tổng hợp, chúng tôi sử dụng để làm cho các chất xúc táctham gia một One-bước tự assembly thủ tục (xem phần 2 chochi tiết về các thủ tục thử nghiệm). Phương pháp này đã được thông quatừ trước đó các báo cáo tổng hợp của Fe3 + (Zn2 +)-doped g-C3N4kết hợp các vật liệu bởi Wang et al. [33]. Đó là giá trị nhấn mạnh ở đâymặc dù rằng mặc dù những điểm tương đồng trong các cấu trúc giữa CuC3N4 báo cáo ở đây và Fe3 + (Zn2 +)-C3N4 báo cáo trong Ref. [33], nhưcũng như những điểm tương đồng của các phương pháp tổng hợp làm việc trong cả haitrường hợp, nó đã là chỉ Cu-doped g-C3N4 mà chúng tôi đã cho thấy electrocatalytic hoạt động hướng tới H2 tiến hóa phản ứng. Nói cách khác,our attempted tests of electrocatalysis of HER using the Fe3+(Zn2+)-C3N4 materials that we made as reported by Wang et al. [33] aswell as many other types of metal ion containing C3N4 were allunsuccessful.In a typical synthesis, copper(II) salt (e.g., CuCl2) was used asthe source of copper, and dicyandiamide was used as an organicmonomer for making the g-C3N4. When the mixture of copper(II)salt and dicyandiamide was thermally treated at elevated temperature (500 ◦C) under N2 protection, the dicyandiamide becameg-C3N4 while, at the same time, the copper ions were directlyself-assembled in situ within the dicyandiamide-derived g-C3N4,forming the desired Cu-C3N4 materials. The relative amount ofcopper in the Cu-C3N4 material, which can be determined by thermogravimetric (TG) analysis (see below), was varied (or controlled)by changing the molar ratio of copper(II) salt and dicyandiamide. Inthis work, two Cu-C3N4 samples with different amount of copper,denoted hereafter as 0.12Cu-C3N4 and 0.31Cu-C3N4, because themolar ratios of Cu/g-C3N4 in them were found to be 0.12:1.00 and0.31:1.00, respectively, (see below) were synthesized. Pure g-C3N4was also synthesized to serve as a reference material to comparethe structures, properties, and electrocatalytic activities with thoseof Cu-C3N4 materials. The BET surface areas of g-C3N4 and Cu-C3N4materials are found to be nearly similar (e.g., 10 cm2/g and 6 cm2/gcho g-C3N4 và 0.12Cu-C3N4, tương ứng).